Question

A publisher wants to estimate the mean length of time​ (in minutes) all adults spend reading newspapers. To determine this​ estimate, the publisher takes a random sample of 15 people and obtains the results below. From past​ studies, the publisher assumes sigma is 1.9 minutes and that the population of times is normally distributed. 10 10 8 10 10 6 10 11 7 9 7 7 8 12 11 Construct the​ 90% and​ 99% confidence intervals for the population mean. Which interval is​ wider? If​ convenient, use technology to construct the confidence intervals. The​ 90% confidence interval is ​( nothing​, nothing​).​ (Round to one decimal place as​ needed.)

Answer 1

From the data, we have,

We know that the 90% confidence interval for population mean is given by:

We know that the 990% confidence interval for population mean is given by: