Capture 3

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 ¢ is 2.3 minutes and that the population of times is normally distributed. 9 6 8 10 &8 6 7 12 12 1" 1 1 12 9 12 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 ( 8.7 , 10.5 ). (Round to one decimal place as needed.) The 99% confidence interval is ( 8.1, 11.1 ). (Round to one decimal place as needed.) Which interval is wider? ¥ The 99% confidence interval The 90% confidence interval