Question

# The waiting times​ (in minutes) of a random sample of 20 people at a bank have...

The waiting times​ (in minutes) of a random sample of 20 people at a bank have a sample standard deviation of 4.4 minutes. Construct a confidence interval for the population variance sigma squared and the population standard deviation sigma. Use a 90 % level of confidence. Assume the sample is from a normally distributed population. What is the confidence interval for the population variance sigma squared​? ​( nothing​, nothing​) ​(Round to one decimal place as​ needed.) Interpret the results. Select the correct choice below and fill in the answer​ box(es) to complete your choice. ​(Round to one decimal place as​ needed.) A. With 10​% ​confidence, you can say that the population variance is greater than nothing. B. With 90 % ​confidence, you can say that the population variance is between nothing and nothing. C. With 10​% ​confidence, you can say that the population variance is between nothing and nothing. D. With 90 % ​confidence, you can say that the population variance is less than nothing. What is the confidence interval for the population standard deviation sigma​? ​( nothing​, nothing​)​ (Round to one decimal place as​ needed.) Interpret the results. Select the correct choice below and fill in the answer​ box(es) to complete your choice. ​(Round to one decimal place as​ needed.) A. With 90​% ​confidence, you can say that the population standard deviation is greater than nothing minutes. B. With 10​% ​confidence, you can say that the population standard deviation is between nothing minutes and nothing minutes. C. With 90​% ​confidence, you can say that the population standard deviation is between nothing and nothing minutes. D. With 10​% ​confidence, you can say that the population standard deviation is less than nothing minutes. Click to select your answer(s).

The required confidence interval for population variance is (12.2, 36.4),

B. With 90 % ​confidence, you can say that the population variance is between 12.2 and 36.4.

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The required confidence interval for population variance is (3.5, 6.0),

C. With 90​% ​confidence, you can say that the population standard deviation is between 3.5 and 6.0 minutes.

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