A market researcher wanted to determine whether the proportion of coffee drinkers who preferred Brand A increased as a result of an advertising campaign. A random sample of 200 coffee drinkers was selected. The results indicating preference for Brand A or Brand B prior to the beginning of the advertising campaign and after its completion are shown in the following table:

a. At the 0.05 level of significance, is there evidence that the proportion of coffee rinkers who prefer Brand A is lower at the beginning of the advertising campaign than at the end of the advertising campaign?
b. Compute the p-value in (a) and interpret its meaning.

PREFERENCE PRIOR TO ADVERTISING CAMPAIGN PREFERENCE AFTER COMPLETION OF ADVERTISING CAMPAIGN Brand A Brand B Total 110 90 200 101 Brand A Brand B Total 68 123