Exemple 8

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 o is 2 2 minutes and that the population of times is normally distributed 9 8 8 6 12 6 6 10 11 10 8 7 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 ( . ) (Round to one decimal place as needed ) The 99% confidence interval is . (Round to one decimal place as needed ) Which interval is wider