Question: The credit card industry is a highly competitive business, with over 8 billion solicitations each year. In 2008, Visa had 39% of the market, compared with 28% for MasterCard, 15% American Express, 6% Diners Club, and 12% other credit cards. A local financial analyst is interested in determining the current market share for these four categories. For this study, the financial analyst randomly selected 500 households and asked which credit card they primarily used.

The results were as follows.

Visa MasterCard America Express Diners Club Other Credit Cards

182 138 104 22 54

a. Does this study indicate that the population proportions using these credit cards differ from the previous year (2008)? Use a 5% confidence level.

b. What is your best estimate for the p- value?