According to a recent Gallup poll, "More Americans who own credit cards say they always pay the full amount of their credit card balance than did so in the years before the 2008-2009 Great Recession." In 2014, 64% of poll respondents said they always or usually pay the full amount on their credit cards each month. In 2004, 53% of poll respondents answered the same way. Assume a sample size of 1026 for each year.

a. Conduct a hypothesis test to determine if the percentage of American adults in 2014 who say they always or usually pay the full amount on their credit cards each month is at least 5% higher than the percentage of American adults in 2004 who answered similarly. Use \alpha=.05. State your hypotheses, test statistic, p-value, and conclusion.

b. Calculate a 90% confidence interval for p1-p2.