The average U.S. family includes 3.13 persons. To determine whether families in her city tend to be representative in size compared to those across the United States, a city council member selects a simple random sample of 40 families. She finds the average number of persons in a family to be 3.40, with a standard deviation of 1.10.
a. Using a nondirectional hypothesis test and a level of significance of your choice, what conclusion would be reached?
b. For the significance level used in part (a), construct the appropriate confidence interval and verify the conclusion reached in part (a).