Training in statistics :

(A) can help us make use of quick, efficient heuristics rather than slower, more effortful thinking.
(B) improves participants’ abilities to make judgments so that judgment errors will be less likely.
(C) improves participants’ abilities to make judgments but only when they are trained in an abstract way.
(D) provides many benefits but seems not to teach students how to make more accurate judgments.

Answers

Answer 1

Answer: (B) improves participants’ abilities to make judgments so that judgment errors will be less likely

Step-by-step explanation:

Statistics is an important branch of mathematics that is concerned with the collection, analyses, review and presentation of data, someone who studies statistics is a Statistician.

Statistical studies can be applicable in many scientific and research based field.

Tools used in statistics are known as statistical measures which includes mean, variance, variance analysis, skewness, kurtosis, and regression analysis.

Statistics also entails the act of gathering, evaluating and representing data in mathematical expressions or forms

Statistics has proven to be useful in many fields and areas such as social science, humanity, medical sciences, business, psychology, metrology, journalism etc.

Generally, statistics helps in making right and sounds judgment in every aspect of life.


Related Questions

Find the initial value aa, growth/decay factor bb, and growth/decay rate rr for the following exponential function: Q(t)=0.0019(2.22)−3t Q(t)=0.0019(2.22)−3t (a) The initial value is a=a= help (numbers) (b) The growth factor is b=b= help (numbers) (Retain at least four decimal places.) (c) The growth rate is r=r= % help (numbers) (Ensure your answer is accurate to at least the nearest 0.01%) (Note that if rr gives a decay rate you should have r<0r<0.)

Answers

Answer:

a) 0.0019

b) 0.0913

c) 9.13%

Step-by-step explanation:

We are given the following information in the question:

[tex]Q(t)=0.0019(2.22)^{-3t}[/tex]

The standard form of exponential function is

[tex]f(t) = ab^{t}[/tex]

where a is the initial amount and b is the base.

Rewriting the the given function, we have:

[tex]Q(t)=0.0019(2.22)^{-3t}\\Q(t)=0.0019((2.22)^{-3})^t\\Q(t)=0.0019(0.0913)^t[/tex]

a) Initial Value

Putting t = 0, we get,

[tex]Q(0)=0.0019(0.0913)^0 = 0.0019[/tex]

a = 0.0019

b) Growth factor

Comparing, we get, b = 0.0913

c) Growth rate

[tex]\text{Growth factor}\times 100\% = 0.0913\times 100\% = 9.13\%[/tex]

Do teachers find their work rewarding and satisfying? An article reports the results of a survey of 397 elementary school teachers and 268 high school teachers. Of the elementary school teachers, 226 said they were very satisfied with their jobs, whereas 129 of the high school teachers were very satisfied with their work. Estimate the difference between the proportion of all elementary school teachers who are satisfied and all high school teachers who are satisfied by calculating a 95% CI. (Use pelementary − phigh school. Round your answers to four decimal places.)

Answers

Final answer:

To estimate the difference between the proportion of elementary school teachers and high school teachers who are satisfied, we need to calculate a 95% confidence interval. The CI is (0.0181, 0.1589).

Explanation:

To estimate the difference between the proportion of all elementary school teachers who are satisfied and all high school teachers who are satisfied, we need to calculate a 95% confidence interval (CI). First, we calculate the sample proportions for both groups. The sample proportion of elementary school teachers who are very satisfied is 226/397 = 0.5698, and the sample proportion of high school teachers who are very satisfied is 129/268 = 0.4813. Next, we calculate the standard error using the formula: √(phat1*(1-phat1)/n1 + phat2*(1-phat2)/n2), where phat1 and phat2 are the sample proportions and n1 and n2 are the sample sizes. Substituting the values, we get √((0.5698*(1-0.5698)/397 + 0.4813*(1-0.4813)/268)). This gives us a standard error of 0.0359.

Next, we need to calculate the margin of error (ME) by multiplying the standard error by 1.96 (which corresponds to a 95% confidence level). ME = 1.96 * 0.0359 = 0.0704.

Finally, we can calculate the confidence interval by subtracting the margin of error from the difference in sample proportions and adding the margin of error to the difference in sample proportions. The difference in sample proportions is 0.5698 - 0.4813 = 0.0885. So, the 95% confidence interval is (0.0885 - 0.0704, 0.0885 + 0.0704), which simplifies to (0.0181, 0.1589).

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Consider the following hypothesis test:H 0: = 17H a: 17A sample of 40 provided a sample mean of 14.12. The population standard deviation is 4.a. Compute the value of the test statistic (to 2 decimals). (If answer is negative, use minus "-" sign.)b. What is the p-value (to 4 decimals)?c. Using = .05, can it be concluded that the population mean is not equal to 17? SelectYesNoItem 3Answer the next three questions using the critical value approach.d. Using = .05, what are the critical values for the test statistic (to 2 decimals)? ±e. State the rejection rule: Reject H 0 if z is Selectgreater than or equal togreater thanless than or equal toless thanequal tonot equal toItem 5 the lower critical value and is Selectgreater than or equal togreater thanless than or equal toless thanequal tonot equal toItem 6 the upper critical value.f. Can it be concluded that the population mean is not equal to 17?

Answers

Answer:

We conclude that the population mean is not equal to 17.

Step-by-step explanation:

We are given the following in the question:

Population mean, μ = 17

Sample mean, [tex]\bar{x}[/tex] = 14.12

Sample size, n = 40

Alpha, α = 0.05

Population standard deviation, σ = 4

First, we design the null and the alternate hypothesis

[tex]H_{0}: \mu = 17\\H_A: \mu \neq 17[/tex]

We use Two-tailed z test to perform this hypothesis.

a) Formula:

[tex]z_{stat} = \displaystyle\frac{\bar{x} - \mu}{\frac{\sigma}{\sqrt{n}} }[/tex]

Putting all the values, we have

[tex]z_{stat} = \displaystyle\frac{14.12 - 17}{\frac{4}{\sqrt{40}} } = -4.5536[/tex]

b) P-value can be calculated from the standard z-table.

P-value = 0.0000

c) Since the p-value is less than the significance level, we reject the null hypothesis and accept the alternate hypothesis. Thus, the population mean is not equal to 17

d) Now, [tex]z_{critical} \text{ at 0.05 level of significance } = \pm 1.96[/tex]

e) Rejection Rule:

We reject the null hypothesis if it is less than lower critical value and greater than the upper critical value

If the z-statistic lies outside the acceptance region which is from -1.96 to +1.96, we reject the null hypothesis.

f) Since the calculated z-stat lies outside the acceptance region, we reject the null hypothesis and accept the alternate hypothesis. Thus, the population mean is not equal to 17.

Final answer:

The test statistic is -1.78 and the p-value is 0.0761, indicating that we fail to reject the null hypothesis. Therefore, it cannot be concluded that the population mean is not equal to 17.

Explanation:

The test statistic can be calculated using the formula:



test statistic = (sample mean - population mean) / (population standard deviation / sqrt(sample size))



Plugging in the given values, we get:



test statistic = (14.12 - 17) / (4 / sqrt(40))



Calculating this gives us a test statistic value of -1.78.



The p-value can be calculated using the test statistic. We need to find the probability that a test statistic at least as extreme as -1.78 would occur assuming the null hypothesis is true. Using a standard normal distribution table or software, we find the p-value to be approximately 0.0761.



Since the p-value is greater than the significance level (alpha = 0.05), we fail to reject the null hypothesis. Therefore, we can conclude that there is not enough evidence to suggest that the population mean is not equal to 17.

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Find the volume of the region bounded by the paraboloid z=x2+y2 and the plane x+y=1 in the first octant.

Answers

Answer:

Step-by-step explanation:

Given

Paraboloid [tex]z=x^2+y^2[/tex] and Plane [tex]x+y=1[/tex] are bounded to get the area

In first octant

value of x varies from [tex]0\leq x\leq 1[/tex]

value of y varies from [tex]0\leq y\leq 1[/tex]

Volume [tex]V=\int_{0}^{1}\int_{0}^{1-x}\left ( x^2+y^2\right )dydx[/tex]

[tex]V=\int_{0}^{1}\left [ x^2y+\frac{y^3}{3}\right ]_{0}^{1-x}[/tex]

[tex]V=\int_{0}^{1}\left [ x^2(1-x)+\frac{(1-x)^3}{3}\right ]dx[/tex]

[tex]V=\int_{0}^{1}\left ( \frac{-4x^3}{3}+2x^2-x+\frac{1}{3}\right )dx[/tex]

[tex]V=\frac{1}{6}[/tex]

The volume of the region bounded by the paraboloid z=x2+y2 and the plane x+y=1 in the first octant is 1/6

The paraboloid and the plane are given as:

[tex]z=x^2+y^2[/tex]

[tex]x+y = 1[/tex]

Make y the subject

[tex]y = 1 - x[/tex]

The plane is in the first octant.

So, the volume is represented as:

[tex]V = \int\limits^1_0 { \int\limits^y_0 {z^2} \, dy } \, dx[/tex]

The integral becomes

[tex]V = \int\limits^1_0 { \int\limits^{1-x}_0 {x^2 + y^2} \, dy } \, dx[/tex]

Integrate with respect to y

[tex]V = \int\limits^1_0 [x^2y + \frac 13y^3]\limits^{1-x}_0 } \, dx[/tex]

Expand

[tex]V = \int\limits^1_0 [x^2(1-x) + \frac 13(1-x)^3]} \, dx[/tex]

Expand

[tex]V = \int\limits^1_0 [x^2-x^3 + \frac 13(1 -x + x^2 - x^3)]} \, dx[/tex]

Expand

[tex]V = \int\limits^1_0 [x^2-x^3 + \frac 13 -x + x^2 - \frac {x^3}3]} \, dx[/tex]

Evaluate the like terms

[tex]V = \int\limits^1_0 [ \frac 13 -x + 2x^2 - \frac {4x^3}3]} \, dx[/tex]

Integrate

[tex]V = [\frac 13x -\frac 12x^2 + \frac 23x^3 - \frac 13x^4]\limits^1_0[/tex]

Expand

[tex]V = \frac 13(1) -\frac 12(1)^2 + \frac 23(1)^3 - \frac 13(1)[/tex]

[tex]V = -\frac 12(1)^2 + \frac 23(1)^3[/tex]

Evaluate the exponents

[tex]V = -\frac 12 + \frac 23[/tex]

Add the fractions

[tex]V = \frac{-3 + 4}{6}[/tex]

[tex]V = \frac{1}{6}[/tex]

Hence, the volume of the region is 1/6

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Wedding expenses and marriage length: With the headline, "Want a happy marriage? Have a big, cheap wedding" CNN reported on a study that examined the correlation between wedding expenses and the length of marriages. The news article states, "A new study found that couples who spend less on their wedding tend to have longer-lasting marriages than those who splurge.What would be a reasonable explanation for the observed correlation? A. Having an inexpensive wedding helps young couples avoid financial burdens that many strain their marriage. B. Having an inexpensive wedding has no impact on the length of marriage because the cost of a wedding is a contounding variable that explains the correlation C. Having an inexpensive wedding guarantees a couple will have a longmarriage the study shows a the term because strong correlation between two variables

Answers

Answer:

A

Step-by-step explanation:

Having an inexpensive wedding helps young couples avoid financial burdens that may strain their marriage. This is true as it will ensure the young couples spend wisely. They understand that if they splurge, the returns will not be as great as that from a long-lasting marriage.

A large room has a temperature of 70 degrees Fahrenheit. When a cup of tea is brought into the room, the tea has a temperature of 120 degrees Fahrenheit. The function f(t)=Ce(−kt)+70 represents the situation, where t is time in minutes, C is a constant, and k is a constant. After 3 minutes the cup of tea has a temperature of 100 degrees. What will be the temperature of the tea, in degrees Fahrenheit, after 5 minutes? Round your answer to the nearest tenth, and do not include units.

Answers

Answer:

91.3

Step-by-step explanation:

Final answer:

To find the temperature of the tea after 5 minutes, use the given function and the information given in the question. By solving the function for the constant C, you can then find the temperature of the tea after 5 minutes.

Explanation:

To find the temperature of the tea after 5 minutes, we need to use the given function and the information given in the question.

First, we can use the given function f(t)=Ce(−kt)+70 to find the value of C. Since we know that after 3 minutes the temperature of the tea is 100 degrees, we can substitute t=3 and T=100 into the function to get:

100 = Ce(−3k)+70

Next, we can use the same function to find the temperature of the tea after 5 minutes. Substituting t=5 into the function and using the value of C that we found earlier, we get:

T = Ce(−5k)+70

Rounding to the nearest tenth, the temperature of the tea after 5 minutes will be approximately 89.4 degrees Fahrenheit.

Ok this time I will fix my English so here I go...

Jonas practices guitar 2 hours a day for 2 years. Bradley practices the guitar 5 hours a day more then Jonas. How many more minutes does Bradley practices the guitar the Jonas over the course of 3 years?

Answers

Answer:Bradley practices for 328500 minutes more than Jonas

Step-by-step explanation:

Jonas practices guitar 2 hours a day for 2 years. 24 hours make a day. Assuming there are 365 days in a year.

If he plays 2 hours for 2 days

Number of hours for which he practiced for 365 days would be (365×2)/2 = 365 hours.

Over the course of 3 years, number of hours for which he practiced would be 365×3 = 1095 hours

Bradley practices the guitar 5 hours a day more then Jonas. Jonas practiced for 1 hour a day. This means that Bradley practices the guitar for 5+1 = 6 hours a day. In a year, it would be 6×365 = 2190 hours. In 3 years, it would be 3×2190 = 6570 hours

Difference in number of hours between Bradley and Jonas is

6570 - 1095 = 5475 hours. Since 60 minutes = 1 hour,

5475 hours would be

5475×60 = 328500 minutes.

Suppose a lawn and garden company wants to determine the current percentage of customers who use fertilizer on their lawns. How many customers should the company survey in order to be 95% confident that the estimated (sample) proportion is within 4 percentage points of the true population proportion of customers who use fertilizer on their lawns?

Answers

Answer:

n=601

Step-by-step explanation:

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".  

The margin of error is the range of values below and above the sample statistic in a confidence interval.  

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".  

The population proportion have the following distribution

[tex]p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})[/tex]

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by [tex]\alpha=1-0.95=0.05[/tex] and [tex]\alpha/2 =0.025[/tex]. And the critical value would be given by:

[tex]z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96[/tex]

The confidence interval for the mean is given by the following formula:  

[tex]\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}[/tex]

The margin of error for the proportion interval is given by this formula:  

[tex] ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}[/tex]    (a)  

And on this case we have that [tex]ME =\pm 0.04[/tex] and we are interested in order to find the value of n, if we solve n from equation (a) we got:  

[tex]n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}[/tex]   (b)  

Since we don't have a prior estimation for the proportion we can use 0.5 as estimation. And replacing into equation (b) the values from part a we got:

[tex]n=\frac{0.5(1-0.5)}{(\frac{0.04}{1.96})^2}=600.25[/tex]  

And rounded up we have that n=601

For each situation, state the null and alternative hypotheses: (Type "mu" for the symbol μ , e.g. mu > 1 for the mean is greater than 1, mu < 1 for the mean is less than 1, mu not = 1 for the mean is not equal to 1. Please do not include units such as "mm" or "$" in your answer.)

a) The diameter of a spindle in a small motor is supposed to be 2.5 millimeters (mm) with a standard deviation of 0.17 mm. If the spindle is either too small or too large, the motor will not work properly. The manufacturer measures the diameter in a sample of 17 spindles to determine whether the mean diameter has moved away from the required measurement. Suppose the sample has an average diameter of 2.57 mm.

H0:

Ha:

(b) Harry thinks that prices in Caldwell are lower than the rest of the country. He reads that the nationwide average price of a certain brand of laundry detergent is $16.35 with standard deviation $2.20. He takes a sample from 3 local Caldwell stores and finds the average price for this same brand of detergent is $14.40.

H0:

Ha:

Answers

Answer:

Part (A) [tex]H_0:\mu=2.5[/tex] and [tex]H_a:\mu\neq2.5[/tex]

Part (B) [tex]H_0:\mu=16.35[/tex] and [tex]H_a:\mu<16.35[/tex]

Step-by-step explanation:

Consider the provided information.

Null hypothesis refers the population parameter is equal to the claimed value.

If there is no statistical significance in the test then it is know as the null which is denoted by [tex]H_0[/tex], otherwise it is known as alternative hypothesis denoted by [tex]H_a[/tex].

Part (A): The diameter of a spindle in a small motor is supposed to be 2.5 millimeters (mm) if the spindle is either too small or too large, the motor will not work properly.

Thus, the required null and alternative hypothesis are:

[tex]H_0:\mu=2.5[/tex] and [tex]H_a:\mu\neq2.5[/tex]

Part (B) The nationwide average price of a certain brand of laundry detergent is $16.35 and Harry thinks that prices in Caldwell are lower than the rest of the country.

Thus, the required null and alternative hypothesis are:

[tex]H_0:\mu=16.35[/tex] and [tex]H_a:\mu<16.35[/tex]

Final answer:

The null and alternative hypotheses for the given situations are as follows: a) H0: μ = 2.5 mm, Ha: μ ≠ 2.5 mm. b) H0: μ = $16.35, Ha: μ < $16.35.

Explanation:

a) H0: The mean diameter of the spindles is 2.5 mm (μ = 2.5 mm).

Ha: The mean diameter of the spindles is not equal to 2.5 mm (μ ≠ 2.5 mm).

b) H0: The mean price of the laundry detergent in Caldwell is $16.35 (μ = $16.35).

Ha: The mean price of the laundry detergent in Caldwell is less than $16.35 (μ < $16.35).

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The Environmental Club is selling water bottles for $8 and tote bags for $12 to raise $240 to donate to charity. Write the linear equation for fundraising goal

Answers

Answer:the linear equation for the fundraising goal is 8x + 12y = 240

Step-by-step explanation:

Let x represent the number of water bottles that the Environmental Club would sell.

Let x represent the number of tote bags that the Environmental Club would sell.

The Environmental Club is selling water bottles for $8 and tote bags for $12 to raise $240 to donate to charity. This means that

8x + 12y = 240

A market research group is interested in comparing the mean weight loss for two different popular diets. The researcher chooses two random samples of participants for the two diet programs. For Diet A, the mean weekly weight loss for 10 participants was 1.5 pounds with standard deviation 0.4 pounds. For Diet B, the mean weekly weight loss for 12 participants was 1.2 pounds with standard deviation 0.6 pounds. At a 5% significance level, does this indicate that Diet A is better than Diet B?

Answers

Answer:

ok

Step-by-step explanation:Jawo

A market research group is interested in comparing the mean weight loss for two different popular diets. And this indicates that Diet A is better than Diet B.

What is hypothesis?

An assumption or concept is given as a hypothesis for the purpose of debating it and testing if it might be true.

Given:

For diet A :

Let n₁ = 10 and X₁ = 1.5, σ₁ = 0.4

For diet B:

Let n₂ = 12 and X₂ = 1.2, σ₂ = 0.6

And α = 0.05

Hypothesis:

H₀: μ₁ = μ₂

H₁ : μ₁ > μ₂

The test:

t =   (x₁ - x₂)  / S√(1/n₁ + 1/n₂)

Where S = √(n₁σ₁² + n₂σ₂²)/(n₁+n₂-2)

S = √(1.6+4.32)/(20)

S= √(0.296)

S = 0.544

Now substituting the value of S to the test.

t =  (x₁ - x₂) / S√(1/n₁ + 1/n₂)

t = (1.5-1.2)/ (0.544)√(1/10 + 1/12)

t = (0.3) / (0.544)(0.428)

t = (0.3) / (0.2329)

t = 1.29

So the p-value is 0.212463888

Here,  α = 0.05 > 0.212463888

If P value < α  then reject H₀ at % level of significance, accept otherwise.

H₁ : μ₁ > μ₂

So, Diet A is better than Diet B

Therefore, diet A is better than diet B

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Suppose we are testing people to see if the rate of use of seat belts has changed from a previous value of 88%. Suppose that in our random sample of 500 people, we see that 450 have the seat belt fastened. (a) About how many of 500 would we expect to be using their seat belts if the proportion who use seat belts is unchanged?

(b) We observe 450 people out of a random sample of 500 using their seatbelt. The p-value is 0.167. Explain the meaning of the p-value.

Answers

Answer:

a) We would expect to see 500*0.88=440

b) [tex]z=\frac{0.9 -0.88}{\sqrt{\frac{0.88(1-0.88)}{500}}}=1.376[/tex]  

[tex]p_v =2*P(Z>1.376)=0.167[/tex]  

So the p value obtained was a very high value and using the significance level assumed [tex]\alpha=0.05[/tex] we have [tex]p_v>\alpha[/tex] so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the true proportion is not significant different from 0.9.

The p value is a criterion to decide if we reject or not the null hypothesis, when [tex]p_v <\alpha[/tex] we reject the null hypothesis in other case we FAIL to reject the null hypothesis. And represent the "probability of obtaining the observed results of a test, assuming that the null hypothesis is correct".  

Step-by-step explanation:

Data given and notation

n=500 represent the random sample taken

X=450 represent the people that have the seat belt fastened

[tex]\hat p=\frac{450}{500}=0.9[/tex] estimated proportion of people that have the seat belt fastened

[tex]p_o=0.88[/tex] is the value that we want to test

[tex]\alpha[/tex] represent the significance level

z would represent the statistic (variable of interest)

[tex]p_v{/tex} represent the p value (variable of interest)  

Part a

We would expect to see 500*0.88=440

Part b

Concepts and formulas to use  

We need to conduct a hypothesis in order to test the claim that the true proportion changes fro m 0.88.:  

Null hypothesis:[tex]p=0.88[/tex]  

Alternative hypothesis:[tex]p \neq 0.88[/tex]  

When we conduct a proportion test we need to use the z statisitc, and the is given by:  

[tex]z=\frac{\hat p -p_o}{\sqrt{\frac{p_o (1-p_o)}{n}}}[/tex] (1)  

The One-Sample Proportion Test is used to assess whether a population proportion [tex]\hat p[/tex] is significantly different from a hypothesized value [tex]p_o[/tex].

Calculate the statistic  

Since we have all the info requires we can replace in formula (1) like this:  

[tex]z=\frac{0.9 -0.88}{\sqrt{\frac{0.88(1-0.88)}{500}}}=1.376[/tex]  

Statistical decision  

It's important to refresh the p value method or p value approach . "This method is about determining "likely" or "unlikely" by determining the probability assuming the null hypothesis were true of observing a more extreme test statistic in the direction of the alternative hypothesis than the one observed". Or in other words is just a method to have an statistical decision to fail to reject or reject the null hypothesis.  

The significance level assumed is [tex]\alpha=0.05[/tex]. The next step would be calculate the p value for this test.  

Since is a bilateral test the p value would be:  

[tex]p_v =2*P(Z>1.376)=0.167[/tex]  

So the p value obtained was a very high value and using the significance level assumed [tex]\alpha=0.05[/tex] we have [tex]p_v>\alpha[/tex] so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can said that at 5% of significance the true proportion is not significant different from 0.9.

The p value is a criterion to decide if we reject or not the null hypothesis, when [tex]p_v <\alpha[/tex] we reject the null hypothesis in other case we FAIL to reject the null hypothesis. And represent the "probability of obtaining the observed results of a test, assuming that the null hypothesis is correct".  

let G be the set of all polynomials of the form ax^2+bx+c with coefficients from the set {0, 1, 2}. we can make G a group under addition by adding the polynomials in the usual way, except that we use modulo 3 to combine the coefficients. with this operation, prove that G is a group of order 27 that is not cyclic

Answers

Answer: All the statements can be proved using definitions from group theory.

Step-by-step explanation:

We will use the fact that the set [tex]\{0,1,2\}:=\mathbb{Z}_3[/tex] is a group under addition modulo 3 (denoted by +). This is because addition modulo 3 is associative, 0 is the identity element for this group and -0=0, -1=2, -2=1.

Let [tex]ax^2+bx+c,dx^2+ex+f, gx^2+hx+i \in G[/tex].

Addition in G is well defined, because [tex]ax^2+bx+c+dx^2+ex+f=(a+d)x^2+(b+e)x+(c+f)[/tex] and the coefficients of this last polynomial are computed using addition modulo 3, which is well defined.

Because addition modulo 3 is associative, we have that [tex](ax^2+bx+c+dx^2+ex+f)+gx^2+hx+i=((a+d)x^2+(b+e)x+(c+f))+gx^2+hx+i=((a+d)+g)x^2+((b+e)+h)x+((c+f)+i)=(a+(d+g))x^2+(b+(e+h))x+(c+(f+i))=ax^2+bx+c+dx^2+((d+g)x^2+(e+h)x+c+(f+i))=ax^2+bx+c+dx^2+(dx^2+ex+f+gx^2+hx+i)[/tex] therefore the addition defined in G is associative.

The identity element for this group is the polynomial [tex]e=0:=0x^2+0x+0\in G[/tex]. Indeed, we have that  [tex]ax^2+bx+c+0=(a+0)x^2+(b+0)x+(c+0)=ax^2+bx+c=(0+a)x^2+(0+b)x+(0+c)=0+ax^2+bx+c[/tex]

The inverse element of a polynomial [tex]ax^2+bx+c \in G[/tex] is the polynomial [tex](-a)x^2+(-b)x+(-c) \in G[/tex], because [tex]ax^2+bx+c+(-a)x^2+(-b)x+(-c)=(a-a)x^2+(b-b)x+(c-c)=0=(-a)x^2+(-b)x+(-c)+]ax^2+bx+c [/tex]

This group has order 27: to count all the polynomials in G we have to count the number of ways to choose a, b and c and construct a polynomial. a,b and c can be either 0,1 or 2 so each one can be chosen in 3 ways. In total, there are 3×3×3=27 possible choices that result in a element of G.

This group is not cyclic. Take any polynomial [tex]ax^2+bx+c \in G[/tex], then its generated group is the set [tex]<ax^2+bx+c>=\{0,ax^2+bx+c,2ax^2+2bx+2c\}[/tex]. This is because any element of the form[tex]n(ax^2+bx+c)=nax^2+nbx+nc, n\in \mathbb{Z}[/tex] can be reduced to [tex](n\mod 3)ax^2+(n\mod 3)bx+(n\mod 3)c[/tex] and [tex]n\mod 3[/tex] only takes the values 0,1,2. The generated group of any element of G has less than 27 elements, so G can't be cyclic.  

Final answer:

The set G of all polynomials ax^2+bx+c with coefficients {0, 1, 2} forms a group under addition with modulo 3 and has order 27, but it is not cyclic, because no element of G, when raised to each power from 0 to the group's order, can generate all elements of G.

Explanation:

Let G be the set of all polynomials of the form ax^2+bx+c, with coefficients {0, 1, 2}. Each coefficient has 3 possibilities (0, 1, 2) so there are 3^3 = 27 total polynomials, hence the order of G is 27.

To show that G is a group under addition with modulo 3, we need to show four things: closure, associativity, identity element, and inverses. Polynomials form a ring under normal addition and multiplication, and since mod 3 addition follows the same rules, G is closed and associative. The identity element is the polynomial where all coefficients are 0. Finally, regarding inverses, every element in G has an additive inverse in G (for example, the inverse of 2 is 1 mod 3).

To show that G is not cyclic, note that a group is cyclic if and only if it has a generator which, when raised to every power from 0 to the order of the group, generates every element of the group. But in G there is no such polynomial, hence G is not cyclic.

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A guidance counselor at a university is investigating demand for study abroad. The question before her is how engineering and humanities majors compare regarding interest in study abroad during summer. Random samples of 20 engineering and humanities majors each were interviewed. Eight engineering majors and 12 humanities majors expressed interest in study abroad during the summer. The estimated difference in the proportion of engineering and humanities majors, p E − p H , where pE is the proportion of engineering majors interested in study abroad and pH is the proportion for humanities, has sampling distribution:a. with mean μ=0.2 and standard deviation σ=0.1549 shape not known.b. Normal with mean μ= -0.2 and standard deviation σ=0.1549.c. Normal with mean μ= 0.2 and standard deviation σ=0.1549. d. with mean μ=-0.2 and standard deviation σ=0.1549 shape not known

Answers

Answer:

[tex]\mu_{p_E -p_H} = 0.4-0.6 =-0.2[/tex]

[tex]SE_{p_E -p_H}=\sqrt{\frac{0.4(1-0.4)}{20} +\frac{0.6 (1-0.6)}{20}}=0.1549[/tex]

b. Normal with mean μ= -0.2 and standard deviation σ=0.1549

Step-by-step explanation:

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".  

[tex]p_E[/tex] represent the real population proportion for Engineering

[tex]\hat p_E =\frac{8}{20}=0.4[/tex] represent the estimated proportion for Engineering

[tex]n_E=20[/tex] is the sample size required for Engineering

[tex]p_H[/tex] represent the real population proportion for Humanities  

[tex]\hat p_H =\frac{12}{20}=0.6[/tex] represent the estimated proportion for Humanities

[tex]n_H=20[/tex] is the sample size required for Humanities

We assume that the population proportions follows a normal distribution since we satisfy these conditions:

[tex]np\geq 5[/tex] ,[tex]n(1-p)\geq 5[/tex]

[tex]20*0.4= 8\geq 5 , 20(1-0.4)=12\geq 5[/tex]

The population proportion have the following distribution  

[tex]p \sim N(p,\sqrt{\frac{p(1-p)}{n}})[/tex]  

And we are interested on the distribution for [tex]p_E-p_H[/tex]

For this case we know that the distribution for the differences of proportions is also normal and given by:

[tex]p_E -p_H \sim N(\hat p_E -\hat p_H, \sqrt{\frac{\hat p_E(1-\hat p_E)}{n_E} +\frac{\hat p_H (1-\hat p_H)}{n_H}}[/tex]

So then we can find the mean and the deviation like this:

[tex]\mu_{p_E -p_H} = 0.4-0.6 =-0.2[/tex]

[tex]SE_{p_E -p_H}=\sqrt{\frac{0.4(1-0.4)}{20} +\frac{0.6 (1-0.6)}{20}}=0.1549[/tex]

So then the best option is :

b. Normal with mean μ= -0.2 and standard deviation σ=0.1549

The shape is unknown since there is no knowledge about it and the representative sample is limited.

Given that;

Total number of interview in engineering and humanities = 20

Number of interview in engineering = 8

Number of interview in humanities = 12

Computation:

⇒ Probability of interview in engineering - Probability of interview in humanities

⇒ 8/20 - 12/20

⇒ -0.20

The shape is unknown since there is no knowledge about it and the representative sample is limited.

Therefore, Option D is the right answer.

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Use the inner product〈f,g〉=∫10f(x)g(x)dxin the vector space C0[0,1] of continuous functions on the domain [0,1] to find 〈f,g〉, ∥f∥, ∥g∥, and the angle αf,g between f(x) and g(x) forf(x)=−10x2−6 and g(x)=−9x−4.〈f,g〉= ,∥f∥= ,∥g∥= ,αf,g .

Answers

Final answer:

The answer to this problem involves applying integrals, norms, and concepts of angles between vectors to the functions f(x) and g(x). The INNER PRODUCT is the integral of the products of the two functions, the norms are the square roots of the inner products of the functions with themselves, and the angle between the functions is calculated using the dot product and norms.

Explanation:

To find the inner product 〈f,g〉, the norms ∥f∥ and ∥g∥, and the angle αf,g between the functions f(x)=−10x2−6 and g(x)=−9x−4, we'll apply concepts from vector calculus. The inner product (also known as the dot product) is the integral from 0 to 1 of the products of the two functions. The norm of a function is the square root of the inner product of the function with itself. The angle between two vectors in a Vector Space, in this case the space of continuous functions C0[0,1], is given by cos(α) = 〈f,g〉/( ∥f∥∙ ∥g∥). Integrating and solving these equations will give us the desired values.

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These are the corrected values for the inner product, norms, and angle between [tex]\(f(x)\)[/tex] and [tex]\(g(x)\)[/tex]in the vector space [tex]\(C^0[0,1]\).[/tex]

1. The inner product \(\langle f,g \rangle\) is given by the integral [tex]\(\int_{1}^{0} f(x)g(x) \, dx\).[/tex] We will compute this integral with[tex]\(f(x) = -10x^2 - 6\) and \(g(x) = -9x - 4\).[/tex]

[tex]\[ \langle f,g \rangle = \int_{1}^{0} (-10x^2 - 6)(-9x - 4) \, dx \][/tex]

 Expanding the integrand, we get:

[tex]\[ \int_{1}^{0} (90x^3 + 40x^2 + 54x + 24) \, dx \][/tex]

Integrating term by term, we have:

[tex]\[ \left[ \frac{90}{4}x^4 + \frac{40}{3}x^3 + \frac{54}{2}x^2 + 24x \right]_{1}^{0} \][/tex]

[tex]\[ = \left( \frac{90}{4} \cdot 0^4 + \frac{40}{3} \cdot 0^3 + \frac{54}{2} \cdot 0^2 + 24 \cdot 0 \right) - \left( \frac{90}{4} \cdot 1^4 + \frac{40}{3} \cdot 1^3 + \frac{54}{2} \cdot 1^2 + 24 \cdot 1 \right) \][/tex]

[tex]\[ = - \left( \frac{90}{4} + \frac{40}{3} + \frac{54}{2} + 24 \right) \][/tex]

[tex]\[ = - \left( 22.5 + 13.333 + 27 + 24 \right) \][/tex]

[tex]\[ = -87.833 \][/tex]

So, [tex]\(\langle f,g \rangle = -87.833\).[/tex]

2. The norm of f is given by [tex]\(\|f\|[/tex] = [tex]\sqrt{\langle f,f \rangle}\)[/tex], where:

[tex]\[ \langle f,f \rangle = \int_{1}^{0} (-10x^2 - 6)^2 \, dx \][/tex]

[tex]\[ = \int_{1}^{0} (100x^4 + 120x^2 + 36) \, dx \][/tex]

[tex]\[ = \left[ \frac{100}{5}x^5 + \frac{120}{3}x^3 + 36x \right]_{1}^{0} \][/tex]

[tex]\[ = - \left( \frac{100}{5} + \frac{120}{3} + 36 \right) \][/tex]

[tex]\[ = - \left( 20 + 40 + 36 \right) \][/tex]

[tex]\[ = -96 \][/tex]

[tex]\[ \|f\| = \sqrt{96} \][/tex]

3. Similarly, the norm of g is given by [tex]\(\|g\|[/tex] = [tex]\sqrt{\langle g,g \rangle}\)[/tex], where:

[tex]\[ \langle g,g \rangle = \int_{1}^{0} (-9x - 4)^2 \, dx \][/tex]

[tex]\[ = \int_{1}^{0} (81x^2 + 72x + 16) \, dx \][/tex]

[tex]\[ = \left[ \frac{81}{3}x^3 + 36x^2 + 16x \right]_{1}^{0} \][/tex]

[tex]\[ = - \left( \frac{81}{3} + 36 + 16 \right) \][/tex]

[tex]\[ = - \left( 27 + 36 + 16 \right) \][/tex]

[tex]\[ = -79 \][/tex]

[tex]\[ \|g\| = \sqrt{79} \][/tex]

4. The angle \[tex](\alpha_{f,g}\)[/tex] between [tex]\(f(x)\)[/tex] and [tex]\(g(x)\)[/tex] is found using the formula:

[tex]\[ \cos(\alpha_{f,g}) = \frac{\langle f,g \rangle}{\|f\| \cdot \|g\|} \][/tex]

[tex]\[ \alpha_{f,g} = \cos^{-1}\left(\frac{-87.833}{\sqrt{96} \cdot \sqrt{79}}\right) \][/tex]

[tex]\[ \langle f,g \rangle = -87.833, \quad \|f\| = \sqrt{96}, \quad \|g\| = \sqrt{79}, \quad \alpha_{f,g} = \cos^{-1}\left(\frac{-87.833}{\sqrt{96} \cdot \sqrt{79}}\right) \][/tex]

The correct calculations for the inner product and norms should be as follows:

[tex]\[ \langle f,g \rangle = \int_{0}^{1} (90x^3 + 40x^2 + 54x + 24) \, dx \][/tex]

[tex]\[ \|f\| = \sqrt{\int_{0}^{1} (100x^4 + 120x^2 + 36) \, dx} \][/tex]

[tex]\[ \|g\| = \sqrt{\int_{0}^{1} (81x^2 + 72x + 16) \, dx} \][/tex]

The angle calculation remains the same. Let's correct the integrals:

[tex]\[ \langle f,g \rangle = \left[ \frac{90}{4}x^4 + \frac{40}{3}x^3 + \frac{54}{2}x^2 + 24x \right]_{0}^{1} \][/tex]

[tex]\[ = \frac{90}{4} + \frac{40}{3} + \frac{54}{2} + 24 \][/tex]

[tex]\[ = \frac{90}{4} + \frac{40}{3} + \frac{54}{2} + 24 \][/tex]

[tex]\[ = 87.833 \][/tex]

So,[tex]\(\langle f,g \rangle = 87.833\).[/tex]

[tex]\[ \|f\| = \sqrt{\left[ \frac{100}{5}x^5 + \frac{120}{3}x^3 + 36x \right]_{0}^{1}} \][/tex]

[tex]\[ = \sqrt{20 + 40 + 36} \][/tex]

[tex]\[ = \sqrt{96} \][/tex]

[tex]\[ \|g\| = \sqrt{\left[ \frac{81}{3}x^3 + 36x^2 + 16x \right]_{0}^{1}} \][/tex]

[tex]\[ = \sqrt{27 + 36 + 16} \][/tex]

[tex]\[ = \sqrt{79} \][/tex]

The corrected values are:

[tex]\[ \langle f,g \rangle = 87.833, \quad \|f\| = \sqrt{96}, \quad \|g\| = \sqrt{79} \][/tex]

The angle calculation remains the same:

[tex]\[ \alpha_{f,g} = \cos^{-1}\left(\frac{87.833}{\sqrt{96} \cdot \sqrt{79}}\right) \][/tex]

A​ hot-air balloon is 140 ft140 ft above the ground when a motorcycle​ (traveling in a straight line on a horizontal​ road) passes directly beneath it going 60 mi divided by hr60 mi/hr ​(88 ft divided by s88 ft/s​). If the balloon rises vertically at a rate of 14 ft divided by s14 ft/s​, what is the rate of change of the distance between the motorcycle and the balloon 10 seconds10 seconds ​later?

Answers

Answer:

Step-by-step explanation:

Given

Balloon velocity is 14 ft/s upwards  

Distance between balloon and cyclist is 140 ft

Velocity of motor cycle is 88 ft/s

After 10 sec  

motorcyclist traveled a distance of [tex]d_c=88\times 10=880 ft[/tex]

Distance traveled by balloon in 10 s

[tex]d_b=14\times 10=140 ft[/tex]

net height of balloon from ground =140+140=280 ft[/tex]

at [tex]t=10 s[/tex]

distance between cyclist and balloon is [tex]z=\sqrt{280^2+880^2}[/tex]

[tex]z=923.47 ft[/tex]

now suppose at any time t motorcyclist cover a distance of x m and balloon is at a height of h m

thus [tex]z^2=(88t)^2+(14t+140)^2[/tex]

differentiating w.r.t time

[tex]\Rightarrow z\frac{\mathrm{d} z}{\mathrm{d} t}=14\cdot \left ( 14t+140\right )+88\cdot \left ( 88t\right )[/tex]

[tex]\Rightarrow at\ t=10 s[/tex]

[tex]\Rightarrow \frac{\mathrm{d} z}{\mathrm{d} t}=\frac{14\cdot \left ( 14t+140\right )+88\cdot \left ( 88t\right )}{z}[/tex]

[tex]\Rightarrow \frac{\mathrm{d} z}{\mathrm{d} t}=\frac{14\times 280+88^2\times 10}{923.471}[/tex]

[tex]\Rightarrow \frac{\mathrm{d} z}{\mathrm{d} t}=\frac{81,360}{923.471}=88.102\ ft/s[/tex]

Drawing a 2, then drawing another 2?

Answers

The probability of drawing a 2 and then drawing another 2 in the board game is 1/72.

To calculate the probability of drawing a 2 and then drawing another 2 in the board game, we first need to understand the concept of probability. Probability represents the likelihood of an event occurring, ranging from 0 (impossible) to 1 (certain). In this case, we're interested in the probability of two specific events happening sequentially: first drawing a 2, and then drawing another 2.

In the board game scenario, there are 9 numbers in total. So, the probability of drawing a 2 on the first draw is 1 out of 9 since there's one 2 among the nine numbers. After drawing the first number and not replacing it, there are now 8 numbers left. If the first draw was a 2, then there's one less 2 available among the remaining 8 numbers. So, the probability of drawing another 2 on the second draw is 1 out of 8.

To find the overall probability of both events happening in sequence (drawing a 2 and then drawing another 2), we multiply the probabilities of each event. Thus, the probability of drawing a 2 and then drawing another 2 is (1/9) * (1/8) = 1/72.

Therefore, the probability of drawing a 2 and then drawing another 2 in the board game is indeed 1/72. This means that out of all the possible sequences of two draws without replacement, only 1 out of 72 sequences will result in drawing a 2 followed by another 2.

Complete question :- In a board game, students draw a number do not replace it and then draw a second number

Determine the probability of each event occurring,

1

6

6

9

21

62

What is the probability of drawing a 2, then drawing another 2?

The number of traffic accidents occurring on any given day in Coralville is Poisson distributed with mean 5. The probability that any such accidentinvolves an uninsured driver is 0.25, independent of all other such accidents.


Calculate the probability that on a given day in Coralville there are no trafficaccidents that involve an uninsured driver.



The answer is 0.278. Could you please explain why?

Answers

Answer:

The answer is 0.2865

Step-by-step explanation:

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]

In which

x is the number of sucesses

e = 2.71828 is the Euler number

[tex]\mu[/tex] is the mean in the given time interval.

In this problem, we have that:

The mean number of accidents on any given day in Coralville is 5. Of those, 25% are with an uninsured drive.

So [tex]\mu = 5*0.25 = 1.25[/tex]

Calculate the probability that on a given day in Coralville there are no trafficaccidents that involve an uninsured driver.

This is P(X = 0). So

[tex]P(X = x) = \frac{e^{-\mu}*\mu^{x}}{(x)!}[/tex]

[tex]P(X = 0) = \frac{e^{-1.25}*(1.25)^{0}}{(0)!} = 02865[/tex]

Final answer:

To calculate the probability of no traffic accidents involving uninsured drivers in Coralville, we can use the Poisson distribution formula with a mean of 5 accidents. The probability is approximately 0.00674, or 0.674%.

Explanation:

To calculate the probability that on a given day in Coralville there are no traffic accidents that involve an uninsured driver, we can use the Poisson distribution formula. The Poisson distribution is used to model the number of events occurring in a fixed interval of time or space, given the average rate of occurrence. In this case, the mean number of traffic accidents is 5, and the probability of an accident involving an uninsured driver is 0.25.

The formula for the Poisson distribution is P(X=k) = (e^(-λ) * λ^k) / k!, where λ is the mean number of events and k is the number of events we are interested in.

To find the probability of no traffic accidents involving uninsured drivers, we can plug in λ=5 and k=0 into the formula:

P(X=0) = (e^(-5) * 5^0) / 0!

P(X=0) = e^(-5) / 1 = 0.006737947

Therefore, the probability that on a given day in Coralville there are no traffic accidents that involve an uninsured driver is approximately 0.00674, or 0.674%.

In a study of automobile collision insurance costs, a random sample of n = 35 repair costs of front-end damage caused by hitting a wall at a specified speed had a mean of $1,438. (a) Given that σ = $269 for such data, what can be said with 98% confidence about the maximum error if x = $1, 438 is used as an estimate of the average cost of such repairs.

Answers

Answer: The maximum error = $105.76.

Step-by-step explanation:

Formula to find the maximum error:

[tex]E= z^*\dfrac{\sigma}{\sqrt{n}}[/tex]

, where n= sample size.

[tex]\sigma[/tex] = Population standard deviation

z*= Critical value(two-tailed).

As per given  , we have

[tex]\overline{x}=1438[/tex]

n= 35

[tex]\sigma=269[/tex]

For 98% confidence  , the significance level = [tex]1-0.98=0.02[/tex]

By z-table , the critical value (two -tailed) =[tex]z^* = z_{\alpha/2}=z_{0.01}=2.326[/tex]

Now , the maximum error = [tex]E= (2.326)\dfrac{269}{\sqrt{35}}[/tex]

[tex]E= (2.326)\dfrac{269}{5.9160797831}[/tex]

[tex]E= (2.326)\times45.4692989044=105.761589252\pprox105.76[/tex]

Hence, With 98% confidence level , the maximum error = $105.76.

The TreeDropp’d Fruit Company wants to sell its apples overseas in attractive pink and yellow gift boxes. To design the boxes, the company needs to estimate the average diameter of their apples. A random sample of 50 apples has a mean of 4.1 inches. You assume a population standard deviatino of .4 inches.

A. What is the point estimate in this scenario? Is it an unbiased estimator?

B. What is the critical z-value for a 95% interval?

C. What is the margin of error for a 95% interval in this scenario? Show your work.

Answers

Answer:

a)For this case the best estimator for the true mean is the sample mean [tex]\hat \mu =\bar X[/tex] because:

[tex]E(\bar X)= \frac{\sum_{i=1}^n E(X_i)}{n}[/tex]

And if we assume that each observation [tex]X_1 , X_2,...,X_n [/tex] follows a normal distribution [tex]X_i \sim N(\mu,\sigma)[/tex] then we have:

[tex]E(\bar X)=\frac{1}{n} n\mu =\mu[/tex]

So then yes the [tex]\bar X[/tex[ is a unbiased estimator for the true mean.

b) [tex]z_{\alpha/2}=1.96[/tex]

c) [tex] ME= 1.96 \frac{0.4}{\sqrt{50}}=0.1109[/tex]

Step-by-step explanation:

Previous concepts

The margin of error is the range of values below and above the sample statistic in a confidence interval.  

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".  

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

[tex]\bar X=4.1[/tex] represent the sample mean  

[tex]\mu[/tex] population mean (variable of interest)  

[tex]\sigma=0.4[/tex] represent the population standard deviation  

n=50 represent the sample size  

Assuming the X follows a normal distribution  

[tex]X \sim N(\mu, \sigma=0.4[/tex]

The sample mean [tex]\bar X[/tex] is distributed on this way:

[tex]\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})[/tex]

A. What is the point estimate in this scenario? Is it an unbiased estimator?

For this case the best estimator for the true mean is the sample mean [tex]\hat \mu =\bar X[/tex] because:

[tex]E(\bar X)= \frac{\sum_{i=1}^n E(X_i)}{n}[/tex]

And if we assume that each observation [tex]X_1 , X_2,...,X_n [/tex] follows a normal distribution [tex]X_i \sim N(\mu,\sigma)[/tex] then we have:

[tex]E(\bar X)=\frac{1}{n} n\mu =\mu[/tex]

So then yes the [tex]\bar X[/tex[ is a unbiased estimator for the true mean.

B. What is the critical z-value for a 95% interval?

The next step would be find the value of [tex]\z_{\alpha/2}[/tex], [tex]\alpha=1-0.95=0.05[/tex] and [tex]\alpha/2=0.025[/tex]  

Using the normal standard table, excel or a calculator we see that:  

[tex]z_{\alpha/2}=1.96[/tex]

C. What is the margin of error for a 95% interval in this scenario? Show your work.

The margin of error is given by:

[tex] ME= z_{\alpha/2}\frac{\sigma}{\sqrt{n}}[/tex]

If we replace the values that we have we got:

[tex] ME= 1.96 \frac{0.4}{\sqrt{50}}=0.1109[/tex]

The confidence interval on this case is given by:

[tex]\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}[/tex] (1)

Since we have all the values we can replace:

[tex]4.1 - 1.96\frac{0.4}{\sqrt{50}}=3.989[/tex]  

[tex]4.1 + 1.96\frac{0.4}{\sqrt{50}}=4.211[/tex]  

So on this case the 95% confidence interval would be given by (3.989;4.211)  

The television show Degenerate Housewives has been successful for many years. That show recently had a share of 18, meaning that among the TV sets in use, 18% were tuned to Degenerate Housewives. Assume that an advertiser wants to verify that 18% share value by conducting its own survey, and a pilot survey begins with 12 households have TV sets in use at the time of a Degenerate Housewivesbroadcast.Find the probability that none of the households are tuned to Degenerate Housewives. P(none) =____________ Find the probability that at least one household is tuned to Degenerate Housewives. P(at least one) = __________Find the probability that at most one household is tuned to Degenerate Housewives. P(at most one) = ___________If at most one household is tuned to Degenerate Housewives, does it appear that the 18% share value is wrong? (Hint: Is the occurrence of at most one household tuned to Degenerate Housewives unusual?)

Answers

Answer:

Step-by-step explanation:

Given that the television show Degenerate Housewives has been successful for many years. That show recently had a share of 18, meaning that among the TV sets in use, 18% were tuned to Degenerate Housewives.

Each household is independent of the other and there two outcomes.

X no of households that are tuned to Degenerate Housewives. is Bin (12, 0.18)

the probability that none of the households are tuned to Degenerate Housewives. P(none) =_______0.0924_____

the probability that at least one household is tuned to Degenerate Housewives. P(at least one) = ____1-0.0924 = 0.9076______

the probability that at most one household is tuned to Degenerate Housewives. P(at most one) = _____0.3359______

If at most one household is tuned to Degenerate Housewives, does it appear that the 18% share value is wrong? (Hint: Is the occurrence of at most one household tuned to Degenerate Housewives unusual?)

No 33% is not unusual.

A survey of people on pizza preferences indicated that 55 percent preferred pepperoni only, 30 percent preferred mushroom only, and 15 percent preferred something other than pepperoni and mushroom. Suppose one person who was surveyed will be selected at random. Let P represent the event that the selected person preferred pepperoni, and let M represent the event that the selected person preferred mushroom. Are P and M mutually exclusive events for the people in this survey? (A) Yes, because the joint probability of P and M is greater than 0. B) Yes, because the joint probability of P and M is greater than 1. C)Yes, because the joint probability of P and M is equal to 0. D) No, because the joint probability of P and M is equal to 1. E) No, because the joint probability of P and M is equal to 0.

Answers

Answer:

C) Yes, because the joint probability of P and M is equal to 0.

Step-by-step explanation:

Given that, P represents the event that the selected person preferred pepperoni only.

And M represents the event that the selected person preferred mushroom only.

so, P and M are two mutually exclusive events because two events are mutually exclusive if they do not occur together.

Here, P and M cannot occur at same time.

so, the joint probability of P and M i.e) probability of both P and M to occur at same time is zero.

In the given problem we have 55 percent preferred pepperoni only, 30 percent preferred mushroom only, and 15 percent preferred something other than pepperoni and mushroom. The probability of event can be identified by selecting how many people can chose pepperoni and mushroom.

The correct option is (c)

Given:

Pepperoni preferred by 55 percent.

Mushroom preferred by 30 percent.

The people who preferred other than Mushroom and Pepperoni are 15 percent.

In the given problem, A person can not select both pepperoni and mushroom because percentages of the pizza preferences adds to 1 in this survey. So, the mathematically,

P(P∩M)=0P(P∩M)=0

The above expression indicates the events are mutually exclusive.

Therefore, the joint probability of P and M is equal to 0.

Thus, the correct option is (c)

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A vendor sells ice cream from a cart on the boardwalk. He offers vanilla, chocolate, strawberry, blueberry, and pistachio ice cream, served on either a waffle, sugar, or plain cone. How many different single-scoop ice-cream cones can you buy from this vendor?

Answers

Answer:

The different single-scoop ice-cream cones can you buy from this vendor=12

Step-by-step explanation:

Given that a  vendor sells ice cream from a cart on the boardwalk. He offers vanilla, chocolate, strawberry, blueberry, and pistachio ice cream, served on either a waffle, sugar, or plain cone.

Different types of icecreams are 4

Types of cones are 3

For each ice cream say we can have either waffle, sugar or plain cone.

i.e. for each type of ice cream, we have 3 different cones.

Hence for 4 types of ice creams we have 3*4=12 different single scoop ice creamcones.

Final answer:

There are 15 different single-scoop ice-cream cones that can be bought from the vendor.

Explanation:

To calculate the number of different single-scoop ice-cream cones that can be bought from the vendor, we need to multiply the number of ice cream flavors with the number of cone types. The vendor offers 5 flavors and 3 cone types, so the total number of different single-scoop ice-cream cones that can be bought is 5 x 3 = 15.

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If there is a .20 correlation between SAT scores and high school GPA, SAT scores account for _____ % of the fluctuation in GPA

Answers

Answer:

SAT scores account for 4 % of the fluctuation in GPA

Step-by-step explanation:

Previous concepts

The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.

And in order to calculate the correlation coefficient we can use this formula:

[tex]r=\frac{n(\sum xy)-(\sum x)(\sum y)}{\sqrt{[n\sum x^2 -(\sum x)^2][n\sum y^2 -(\sum y)^2]}}[/tex]  

The determinarion coefficient represent "the proportion of the variance in the dependent variable that is predictable or explained from the independent variable".

And is just defined as [tex]r^2[/tex]

Solution to the problem

The % of variation is given by the determination coefficient given by [tex]r^2[/tex] and on this case [tex]0.2^2 =0.04[/tex], so then the % of variation explained by the linear model is 4%.

And we can conclude that: SAT scores account for 4 % of the fluctuation in GPA

The sum of the first 200 terms of the arithmetic sequence with initial term 2 and common difference 3 is
A. 599B. 601C. 604D. 60100E. 60400

Answers

Answer: D. 60100

Step-by-step explanation:

The formula for determining the sum of n terms of an arithmetic sequence is expressed as

Sn = n/2[2a + (n - 1)d]

Where

n represents the number of terms in the arithmetic sequence.

d represents the common difference of the terms in the arithmetic sequence.

a represents the first term of the arithmetic sequence.

From the information given,

n = 200 terms

a = 2

d = 3

Therefore, the sum of the first 200 terms, S200 would be

S200 = 200/2[2 × 2 + (200 - 1)3]

S200 = 100[4 + 597)

S200 = 100 × 601 = 60100

47.5% of children say that chocolate chip cookie is their favorite kind of cookie. If you randomly select 4 children find the probability that: a) exactly 2 say that chocolate chip cookie is their favorite. c) at least one of the 4 say that chocolate chip cookie is their favorite. d) Find the mean and standard deviation for this sample.

Answers

Answer:

a) 0.3731

b) 0.9241

c) Mean = 1.9

Standard Deviation = 0.9987

Step-by-step explanation:

We are given the following information:

P(chocolate chip cookie) = 47.5% = 0.475

Then the number of children follows a binomial distribution, where

[tex]P(X=x) = \binom{n}{x}.p^x.(1-p)^{n-x}[/tex]

where n is the total number of observations, x is the number of success, p is the probability of success.

Now, we are given n = 4

a) x = 2

We have to evaluate:

[tex]P(x =2)\\= \binom{4}{2}(0.475)^2(1-0.475)^{4-2}\\= 0.3731[/tex]

b) x = 1

We have to evaluate

[tex]P(x \geq 1) = 1 - P(x = 0)\\= 1 - \binom{4}{0}(0.475)^0(1-0.475)^{4-0}\\= 1 - 0.0759\\= 0.9241[/tex]

c) Mean and standard deviation of distribution

[tex]\text{Mean} = np = 4\times 0.475 = 1.9\\\text{Standard deviation} = \sqrt{np(1-p)} = \sqrt{4\times 0.475(1-0.475)} = 0.9987[/tex]

A recent study by a major financial investment company was interested in determining whether the annual percentage change in stock price for companies is linearly related with the annual percent change in profits for the company. The following data was determined for 7 randomly selected companies: Col1 % Change Stock Price (Y) 8.4 9.5 13.6 -3.2 7 18.4 -2.1Col2 % Change in Profit (X) 4.2 5.6 11.2 4.5 12.2 12 -13.4 Based upon this sample information, which of the following is the regression equation? a. y? 1.19-3.00 x b· y?=-4.198-0.612x c. y? =+4.198 x d, y? = 4.198 + 0.612 x

Answers

Answer:

c. y? =+4.198 x

Step-by-step explanation:

Hello!

Using the given data you need to estimate the equation of linear regression.

Dependent variable:

Y: Annual percentage change in stock price for a company.

Independent variable:

X: Annual percentage change in profits for the company.

The population regression line equation is:

[tex]Y_i= \alpha + \beta X_i + E_i[/tex]

To estimate the equation you need to find the point estimator for α and β.

The following formulas are the ones to use:

α ⇒ a= y[bar] - bX[bar]

β ⇒ b= (∑xy - [(∑x)(∑y)]/n)/(∑X²-(∑x)²/n)

As you can see you need to make several summatories before calculating the values of a and b:

n= 7

∑x= 36.30

∑x²= 667.09

∑y= 51.60

∑y²= 747.98

∑xy= 560.74

Sample mean of de dependent variable Y[bar]= ∑y/n= (51.60/7)= 7.37

Sample mean of the independent variable X[bar]= ∑x/n= (36.30/7)= 5.19

b= [tex]\frac{560.74-\frac{(36.3*51.6)}{7} }{667.09-\frac{(51.60)^2}{7} }[/tex]

b= 0.6122

a= [tex]7.37-(0.61*5.19)[/tex]

a= 4.196

The estimated regression equation is:

Y= 4.196 + 0.6122x

I hope it helps!

Consider an experiment with a deck of 52 playing cards, in which there are 13 cards in each suit, two suits are black, and two suits are red. Suppose E1 = the outcome is a red card and E2 = the outcome is a face card (K, Q, J). Determine P(E1 or E2).

Answers

Final answer:

The probability of getting a red card or a face card from a deck of playing cards is 8/13.

Explanation:

To determine P(E1 or E2), we need to find the probability of either event E1 (outcome is a red card) or event E2 (outcome is a face card) occurring.

To find P(E1), we can count the number of red cards in the deck, which is 26 (there are 2 red suits and each suit has 13 cards).

To find P(E2), we can count the number of face cards in the deck, which is 12 (there are 3 face cards in each suit and 4 suits).

Since E1 and E2 are not mutually exclusive (some cards are both red and face cards), we need to subtract the number of cards that satisfy both events to avoid double counting. In this case, there are 6 red face cards in the deck (2 red suits each with 3 face cards).

Therefore, P(E1 or E2) = P(E1) + P(E2) - P(E1 and E2) = 26/52 + 12/52 - 6/52 = 32/52 = 8/13.

Final answer:

The probability of drawing either a red card or a face card from a standard deck of 52 playing cards is 8/13.

Explanation:

To calculate P(E1 or E2), where E1 is the event of drawing a red card and E2 is the event of drawing a face card from a standard deck of 52 playing cards, we can use the formula for the probability of the union of two events: P(E1 or E2) = P(E1) + P(E2) - P(E1 and E2). Since there are 13 red cards in each of the two red suits (hearts and diamonds), P(E1) = 26/52. There are 3 face cards (jack, queen, king) in each of the four suits, so P(E2) = 12/52. However, among these face cards, 6 are red (3 in hearts and 3 in diamonds), so P(E1 and E2) = 6/52. Thus, the probability of drawing either a red card or a face card is P(E1 or E2) = 26/52 + 12/52 - 6/52.

In conclusion: P(E1 or E2) = (26 + 12 - 6) / 52

Simplifying that, we get: P(E1 or E2) = 32/52, which can be reduced to P(E1 or E2) = 8/13.

A group of veterinary researchers plan a study to estimate the average number of enteroliths in horses suffering from them. The number of enteroliths is determined by surgery or ultrasound. This requires the participation of a radiologist and a surgeon in the study. The researchers decide that they should only enroll horses seen at the best veterinary hospital in the country to ensure correct counts. Such a hospital will typically see the most severe cases. The researchers will enroll the first 100 horses seen beginning on the day the study is funded. The resulting interval is likely biased because:
A. the best veterinary hospital is likely to see the most severe cases with larger number of enteroliths.
B. the first 100 horses seen is not an SRS of all horses with enteroliths and therefore never representative.
C. a sample of 100 horses is too small to obtain an unbiased estimate.
D. All of the above.

Answers

The sample of 100 horses is too small to obtain an unbiased estimate.

What is Applied research?

Applied research frequently focuses more on finding solutions to particular issues that directly impact people in the present. As an illustration, a social psychologist conducting fundamental research on violence would consider the various potential causes of violence in general.

Given, A study is being planned by a group of veterinary researchers to determine how many enteroliths are present on average in affected horses. When the study is financed, the researchers will sign up the first 100 horses they observe.

A study plan, which is considered to be the most important piece of information describing the projected research sample of an investigator, is the main part of an application. An important analyst is also given the opportunity to speak on the planned study, highlighting its benefits and explaining the implementation and conduct of the research. Because it covers your whole research project from start to finish and identifies and explains your emphasis, technique, and goals, a research plan is crucial.

Therefore, The sample size of 100 horses is insufficient to provide a fair assessment.

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In March 2015, the Public Policy Institute of California (PPIC) surveyed 7525 likely voters living in California. This is the 148th PPIC research poll, and is part of a survey series that started in 1998. PPIC researchers find that 3266 survey participants are registered Democrats and 2137 survey participants are registered Republicans. PPIC is interested in the difference between the proportion of registered Democrats and the proportion of registered Republicans in California. PPIC researchers calculate that the standard error for the proportion of registered Democrats minus registered Republicans is about 0.008. Of the 3266 registered Democrats, 1894 approve of the way the California Legislature is handling its job. Of the 2137 registered Republicans, 385 approve of the way the California Legislature is handling its job. What is the 90% confidence interval to estimate the difference in approval for the California Legislature based on political party affiliation?

Answers

Answer:

We are confident at 99% that the difference between the two proportions is between [tex]0.380 \leq p_{Republicans} -p_{Democrats} \leq 0.420[/tex]

Step-by-step explanation:

Part a

Data given and notation  

[tex]X_{D}=3266[/tex] represent the number people registered as Democrats

[tex]X_{R}=2137[/tex] represent the number of people registered as Republicans

[tex]n=7525[/tex] sampleselcted

[tex]\hat p_{D}=\frac{3266}{7525}=0.434[/tex] represent the proportion of people registered as Democrats

[tex]\hat p_{R}=\frac{2137}{7525}=0.284[/tex] represent the proportion of people registered as Republicans

The standard error is given by this formula:

[tex]SE=\sqrt{\frac{\hat p_D (1-\hat p_D)}{n_{D}}+\frac{\hat p_R (1-\hat p_R)}{n_{R}}}[/tex]

And the standard error estimated given by the problem is 0.008

Part b

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".  

The margin of error is the range of values below and above the sample statistic in a confidence interval.  

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".  

[tex]p_A[/tex] represent the real population proportion of Democrats that approve of the way the California Legislature is handling its job  

[tex]\hat p_A =\frac{1894}{3266}=0.580[/tex] represent the estimated proportion of Democrats that approve of the way the California Legislature is handling its job  

[tex]n_A=3266[/tex] is the sample size for Democrats

[tex]p_B[/tex] represent the real population proportion of Republicans that approve of the way the California Legislature is handling its job  

[tex]\hat p_B =\frac{385}{2137}=0.180[/tex] represent the estimated proportion of Republicans that approve of the way the California Legislature is handling its job

[tex]n_B=2137[/tex] is the sample for Republicans

[tex]z[/tex] represent the critical value for the margin of error  

The population proportion have the following distribution  

[tex]p \sim N(p,\sqrt{\frac{p(1-p)}{n}})[/tex]  

The confidence interval for the difference of two proportions would be given by this formula  

[tex](\hat p_A -\hat p_B) \pm z_{\alpha/2} \sqrt{\frac{\hat p_A(1-\hat p_A)}{n_A} +\frac{\hat p_B (1-\hat p_B)}{n_B}}[/tex]  

For the 90% confidence interval the value of [tex]\alpha=1-0.90=0.1[/tex] and [tex]\alpha/2=0.05[/tex], with that value we can find the quantile required for the interval in the normal standard distribution.  

[tex]z_{\alpha/2}=1.64[/tex]  

And replacing into the confidence interval formula we got:  

[tex](0.580-0.180) - 1.64 \sqrt{\frac{0.580(1-0.580)}{3266} +\frac{0.180(1-0.180)}{2137}}=0.380[/tex]  

[tex](0.580-0.180) + 1.64 \sqrt{\frac{0.580(1-0.580)}{3266} +\frac{0.180(1-0.180)}{2137}}=0.420[/tex]  

And the 99% confidence interval would be given (0.380;0.420).  

We are confident at 99% that the difference between the two proportions is between [tex]0.380 \leq p_{Republicans} -p_{Democrats} \leq 0.420[/tex]

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