As part of a survey, a marketing representative asks a random sample of 28 business owners how much they would be willing to pay for a website for their company. She finds that the sample standard deviation is $3600. Assume the sample is taken from a normally distributed population. Construct 95% confidence intervals for (a) the population variance o2 and (b) the population standard deviation o. Interpret the results. (a) The confidence interval for the population variance is ( 8100937, 24011528. ) (Round to the nearest integer as needed.) Interpret the results. Select the correct choice below and fill in the answer box(es) to complete your choice. (Round to the nearest integer as needed.) O A. With 5% confidence, you can say that the population variance is between O B. With 95% confidence, you can say that the population variance is between and and OC. With 95% confidence, you can say that the population variance is less D. With 5% confidence, you can say that the population variance is greater than than

You want to buy a washing​ machine, and a salesperson tells you that the mean repair costs for Model A and Model B are equal. You research the repair costs. The mean repair cost of 21 Model A washing machines is $215. Assume the population standard deviation is $19. The mean repair cost of 22 Model B washing machines is $221. Assume the population standard deviation is $20. At α=0.01, can you reject the​ salesperson's claim? Assume the samples are random and​ independent, and the populations are normally distributed.

A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1511 and the standard deviation was 312. The test scores of four students selected at random are 1910, 1280, 2240, and 1420. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The z-score for 1910 is (Round to two decimal places as needed.) The z-score for 1280 is (Round to two decimal places as needed.) The Z-score for 2240 is (Round to two decimal places as needed.) The Z-score for 1420 is (Round to two decimal places as needed.) Which values, if any, are unusual? Select the correct choice below and, if necessary, fill in the answer box within your choice OA. The unusual value(s) is/are (Use a comma to separate answers as needed.) OB. None of the values are unusual.

A population has a mean µ = 87 and a standard deviation o=27. Find the mean and standard deviation of a sampling distribution of sample means with sample size n = 81. (Simplify your answer.)

A hiring company claims that the variance of the annual salaries for managers is greater in Florida than Georgia. You select a sample of 28 managers in Florida and find the standard deviation to be $11,000. You select a sample of 24 managers in Georgia and find the standard deviation to be $9,200. At α=0.05, can you support the hiring company's claim?

You want to buy a washing​ machine, and a salesperson tells you that the mean repair costs for Model A and Model B are equal. You research the repair costs. The mean repair cost of 24 Model A washing machines is ​$209. Assume the population standard deviation is ​$20. The mean repair cost of 27 Model B washing machines is ​$215. Assume the population standard deviation is ​$24. At α=0.01, can you reject the​ salesperson's claim? Assume the samples are random and​ independent, and the populations are normally distributed. Complete parts​ (a) through​ (e). ​(a) Identify the claim and state H0 and Ha.   What is the​ claim?     A. The mean repair costs for Model A and Model B are equal.   B. The mean repair cost for Model A is greater than Model B.   C. The mean repair costs for Model A and Model B are different.   D. The mean repair cost for Model A is less than Model B. Let μ1 be the mean repair cost for Model A and let μ2 be the mean repair cost for Model B.…

The lengths of pregnancies in a small rural village are normally distributed with a mean of 267 days and a standard deviation of 15 days.In what range would you expect to find the middle 95% of most pregnancies?Between  and .If you were to draw samples of size 55 from this population, in what range would you expect to find the middle 95% of most averages for the lengths of pregnancies in the sample?Between  and .

A professor is concerned that the two sections of college algebra that he teaches are not performing at the same level. To test his claim, he looks at the mean exam score for a random sample of students from each of his classes. In Class 1, the mean exam score for 12 students is 80.8 with a standard deviation of 5.7. In Class 2, the mean exam score for 14 students is 84.5 with a standard deviation of 4.9. Test the professor's claim at the 0.01 level of significance. Assume that both populations are approximately normal and that the population variances are equal. Let Class 1 be Population 1 and let Class 2 be Population 2. Step 2 of 3: Compute the value of the test statistic. Round your answer to three decimal places.