Suppose a retailer claims that the average wait time for a customer on its support line is 173 seconds. A random sample of 56 customers had an average wait time of 164 seconds. Assume the population standard deviation for wait time is 50 seconds. Using a 95​% confidence​ interval, does this sample support the​ retailer's claim?

Using a 95​% confidence​ interval, does this sample support the​ retailer's claim? Select the correct choice​ below, and fill in the answer boxes to complete your choice. ​(Round to two decimal places as​ needed.)

A. No​, because the​ retailer's claim is not between the lower limit of nothing seconds and the upper limit of nothing seconds for the mean wait time.

B. Yes​, because the​ retailer's claim is nothing between the lower limit of nothing seconds and the upper limit of nothing seconds for the mean wait time.

Given the following hypothesis:

H0 : μ ≤ 11

H1 : μ > 11

For a random sample of 10 observations, the sample mean was 13 and the sample standard deviation 4.20. Using the .05 significance level:

(a) State the decision rule. (Round your answer to 3 decimal places.)

Reject or don't reject? H0 if t > ?

(b) Compute the value of the test statistic. (Round your answer to 2 decimal places.)

Value of the test statistic :

(c) What is your decision regarding the null hypothesis?

(Reject or dont reject?) H0. The mean (is or is not) greater than 11.

The new candy Green Globules is being test-marketed in an area of upstate New York. The market research firm decided to sample 6 cities from the 45 cities in the area and then to sample supermarkets within cities, wanting to know the number of cases of Green Globules sold.

City

1 2 3 4 5 6

Number of Supermarkets

52 19 37 39 8 14

Number of Cases Sold

146,180,251,152,72,181,171,361,73,186

99,101,52,121

199,179,98,63,126,87,62

226,129,57,46,86,43,85,165

12, 23

87,43,59

Obtain summary statistics for each cluster.

Plot the data, and estimate the total number of cases sold, and the average number sold per supermarket, along with the standard errors of your estimates.

A particular baseball team wins 68% of its games. Next week it will play 6 games. (a) What is the team’s expected number of wins during that week? (Round your answer to 2 decimal places.) (b) What is the probability that the team will win at least 5 games next week?

Use the sample data and confidence level given below to complete parts​ (a) through​ (d).

A research institute poll asked respondents if they felt vulnerable to identity theft. In the​ poll, n equals 930 and x equals 574 who said​ "yes." Use a 99 % confidence level.

​a) Find the best point estimate of the population proportion p. minus ​(Round to three decimal places as​ needed.) ​

b) Identify the value of the margin of error E. Eequals minus ​(Round to three decimal places as​ needed.) ​

c) Construct the confidence interval. minusless than p less than minus ​(Round to three decimal places as​ needed.) ​

d) Write a statement that correctly interprets the confidence interval.

Choose the correct answer below.

A. There is a 99​% chance that the true value of the population proportion will fall between the lower bound and the upper bound.

B. One has 99​% confidence that the sample proportion is equal to the population proportion.

C. 99​% of sample proportions will fall between the lower bound and the upper bound.

D. One has 99​% confidence that the interval from the lower bound to the upper bound actually does contain the true value of the population proportion.

A sample of 50 females is given a test and they score an average of 75 on it. A sample of 36 males is also given the test and score an average of 72 on it. It is known from previous studies that the females have a standard deviation of 10, while the males have on of 12 on this test. At an alpha of .05 is there a significant difference in the true means for the females and the males?

a. Null/Alternate Hypothesis.

b. Test Statistic.

c. Critical regions

d. Reject/Fail to Reject

e. Find the p-value

f. Answer the question.

What is Cramer's V for each of the following values for the chi-square test for independence? (Round your answers to two decimal places.)

(a) X2 = 3.95, n = 50, dfsmaller = 1 V =

(b) X2 = 8.81, n = 110, dfsmaller = 2 V =

(c) X2 = 11.62, n = 180, dfsmaller = 3 V =

Consider the class average in an exam in a few different settings. In all cases, assume that we have a large class consisting of equally well-prepared students. Think about the assumptions behind the central limit theorem, and choose the most appropriate response under the given description of the different settings.

1. Consider the class average in an exam of a fixed difficulty.

a) The class average is approximately normal

b) The class average is not approximately normal because the student scores are strongly dependent

c) The class average is not approximately normal because the student scores are not identically distributed

2. Consider the class average in an exam that is equally likely to be very easy or very hard.

a) The class average is approximately normal

b) The class average is not approximately normal because the student scores are strongly dependent

c) The class average is not approximately normal because the student scores are not identically distributed

3. Consider the class average if the class is split into two equal-size sections. One section gets an easy exam and the other section gets a hard exam.

a) The class average is approximately normal

b) The class average is not approximately normal because the student scores are strongly dependent

c) The class average is not approximately normal because the student scores are not identically distributed

4. Consider the class average if every student is (randomly and independently) given either an easy or a hard exam.

a) The class average is approximately normal

b) The class average is not approximately normal because the student scores are strongly dependent

c) The class average is not approximately normal because the student scores are not identically distributed

Advertisers contract with Internet service providers and search engines to place ads on websites. They pay a fee based on the number of potential customers who click on their ad. Unfortunately, click fraud—the practice of someone clicking on an ad solely for the purpose of driving up advertising revenue—has become a problem. According to BusinessWeek 43% of advertisers claim they have been a victim of click fraud. Suppose a simple random sample of 300 advertisers will be taken to learn more about how they are affected by this practice. Use z-table.

a. What is the probability that the sample proportion will be within +- 0.03 of the population proportion experiencing click fraud?

(to 4 decimals)

b. What is the probability that the sample proportion will be greater than 0.49?

(to 4 decimals)

A survey of the mean number of cents off that coupons give was conducted by randomly surveying one coupon per page from the coupon sections of a recent Rockford newspaper. The following data were collected: 20¢; 75¢; 50¢; 75¢; 30¢; 55¢; 10¢; 40¢; 30¢; 55¢; $1.50; 40¢; 65¢; 40¢. Assume the underlying distribution is approximately normal. Construct a 95% confidence interval for the population mean worth of coupons. Find the lower limit of the confidence interval. Enter it rounded to the nearest cent (2 decimal places)

Let x = red blood cell (RBC) count in millions per cubic millimeter of whole blood. For healthy females, x has an approximately normal distribution with mean μ = 5.2 and standard deviation σ = 0.7.

(a) Convert the x interval, 4.5 < x, to a z interval. (Round your answer to two decimal places.)
< z

(b) Convert the x interval, x < 4.2, to a z interval. (Round your answer to two decimal places.)
z <  

(c) Convert the x interval, 4.0 < x < 5.5, to a z interval. (Round your answers to two decimal places.)
< z <  

(d) Convert the z interval, z < −1.44, to an x interval. (Round your answer to one decimal place.)
x <  

(e) Convert the z interval, 1.28 < z, to an x interval. (Round your answer to one decimal place.)
< x

(f) Convert the z interval, −2.25 < z < −1.00, to an x interval. (Round your answers to one decimal place.)
< x <  

(g) If a female had an RBC count of 5.9 or higher, would that be considered unusually high? Explain using z values.

Yes. A z score of 1.00 implies that this RBC is unusually high.No. A z score of −1.00 implies that this RBC is unusually low.     No. A z score of 1.00 implies that this RBC is normal.

The following 5 questions are based on this information.

A random sample of 25 Apple (the company) customers who call Apple Care Support line had an average (X bar) wait time of 187 seconds with a sample standard deviation (s) of 50 seconds. The goal is to construct a 90% confidence interval for the average (μ) wait time of all Apple customers who call for support.

Assume that the random variable, wait time of Apple customers (denoted by X), is normally distributed.

1) The standard error (SE) of X bar is

Select one:

a. 2

b. 10

c. 50

d. 37.4

2) The critical value (CV) needed for 90% confidence interval estimation is

Select one:

a. 1.28

b. 0.05

c. 1.71

d. 0.1

3) The 90% confidence interval estimate of μ is

Select one:

a. 187 ± 10

b. 187 ± 17.1

c. 187 ± 12.82

d. 187 ± 50

4) Suppose Apple claims that the average wait of a customer is 175 seconds. In light of the sample evidence and at the 10% level of significance,

Select one:

a. We can not reject Apple's claim

b. We can reject Apple's claim

5) If we increase the confidence level (1-α) from 0.90 to 0.95, the margin of error (ME) of the confidence interval estimate will

Select one:

a. decrease

b. be zero

c. increase

d. stays the same

A sample of students from an introductory psychology class were polled regarding the number of hours they spent in studying for the last exam. All students anonymously submitted the number of hours on a 3 by 5 card. There were 24 individuals in the one section of the course polled. There data are below: 4.5, 22, 7, 14.5, 9, 9, 3.5, 8, 11, 7.5, 18, 20, 7.5, 9, 10.5, 15, 19, 2.5, 5, 9, 8.5, 14, 20, 8.

A. based on the sample results, find the 95% confidence interval.

B. Interpret the result

C.Do you expect a 90% confidence interval to be wider or narrower and why.

What is the age distribution of adult shoplifters (21 years of age or older) in supermarkets? The following is based on information taken from the National Retail Federation. A random sample of 895 incidents of shoplifting gave the following age distribution. Estimate the mean age, sample variance, and sample standard deviation for the shoplifters. For the class 41 and over, use 45.5 as the class midpoint. (Round your answers to one decimal place.)

Student affairs departments at colleges provide programs and events that offer students opportunities to learn outside of traditional coursework. One popular avenue of engagement chosen by students is intramural sports. Does participation in intramural sports improve freshmen academic indicators such as GPA and retention after the first year?

This Excel file Freshmen Intramurals has data on 745 intramural participant/nonparticipant pairs of freshmen at a large midwestern university. The student participant/nonparticipant pairs were formed based on matching gender and high school GPA (to within 0.25).

A claim frequently made by college academic advisors is that freshmen intramural participants have higher freshman-year GPA's than freshmen who do not participate in intramurals. Let μ_P be the mean freshmen year GPA of intramural participants and μ_N be the mean freshmen year GPA of intramural nonparticipants. Do these data support the claim that freshmen intramural participants have higher freshmen year mean GPA's than freshmen intramural nonparticipants? Perform the appropriate hypothesis test and answer the questions below (calculate the difference as participant freshmen year GPA - nonparticipant freshmen year GPA.

excel file- https://docs.google.com/spreadsheets/d/e/2PACX-1vS5eS0C7pu0kxQEOPYnJnrWThBOxuYztqXcdjp6xPL06Elf8r4OhwLsjPNk1xdads9Le3Xb2qsZroML/pubhtml?gid=0&single=true

copy the file into a browser

Question 1. What is the value of the test statistic t? (use 2 decimal places in your answer)

Question 2. Select the correct choice below for the P-value of this hypothesis test.

-0.005 < P-value < 0.01

-P-value > 0.10    

-0.05 < P-value < 0.10

-0.01 < P-value < 0.05

-0.001 < P-value < 0.005

-P-value < 0.0001

Question 3. What is an appropriate conclusion for this hypothesis test? (1 submission allowed)

-There is insufficient evidence to conclude that the mean freshmen year GPA of intramural participants is greater than the mean freshmen year GPA of intramural nonparticipant.

-There is sufficient evidence to conclude that the mean freshmen year GPA of intramural participants is greater than the mean freshmen year GPA of intramural nonparticipants.

-There is sufficient evidence to conclude that the mean freshmen year GPA of intramural participants is less than the mean freshmen year GPA of intramural nonparticipants.

Question 4. Estimate the mean difference (freshmen year intramural participant GPA - freshmen year intramural nonparticipant GPA) in freshmen year GPA's with a 95% confidence interval.

- lower bound of interval (use 4 decimal places)

- upper bound of interval (use 4 decimal places)