Complete the full confidence interval procedure for each of the following.
Problem
A college administrator would like to determine how much time students spend on homework assignments during a typical week. A questionnaire is sent to a random sample of n =100 students and their response indicates a mean of 7.4 hours per week. The population standarddeviation is known to be 3 hours. Construct a 95% confidence intervalfor the population mean of the number of hours student spend on homework during a typicalweek.
Problem
In Roosevelt National Forest, the rangers took random samples of live aspen trees and measured the base circumferenceof each tree. Assume that the circumferences of the trees are normally distributed.The average of the 100 trees sampled was 15.71. The population standard deviation is 4.63 inches. Construct a 90% confidence interval for the population mean of the circumference of the aspen tree.
Problem
The number of hours shoppers spend at Wegman's is normally distributed. A random sample of 25 shoppers has a sample mean of 42 minutes. The population standard deviation is 12 minutes. Construct a 99% confidence interval for the population mean of the time shoppers spend at Wegmans.