Assume that the population standard deviation is equal to 35

Assume that the population standard deviation is equal to 3.56, the standard deviation from the NBER study.

Consumers with at least one credit card have a mean of 4.84 credit cards. [Source: Sumit Agarwal, John C. Driscoll, Xavier Gabaix, and David Laibson, \"Learning in the Credit Card Market,\" Working Paper 13822, National Bureau of Economic Research (NBER), February 2008.] You want to test the hypothesis that the mean number of credit cards held by high-income consumers (consumers with annual incomes over $100,000) is different from the reported mean of 4.84. A random sample of 300 high-income consumers provides a sample mean number of credit cards of -4.97. Use a significance level of -.01 for the test. Use a confidence interval estimate approach to conduct the hypothesis test. confidence To use a confidence interval estimate approach to conduct the hypothesis test, you construct the interval estimate of the population mearn. confide

Solution