For each word problem, use a solution sheet to solve the hypothesis test problem. Go to the reference for the chi-square solution sheet. Round expected frequency to two decimal places.
Consumers may be interested in whether the cost of a particular calculator varies from store to store. Based on surveying 43 stores, which yielded a sample mean of $84 and a sample standard deviation of $12, test the claim that the standard deviation is greater than $15.
OpenStax Statistics, 11.6 Test of a Single Variance, exercise 28