Independent random samples of n1 = 1265 and n2 = 1688 observations were selected from binomial populations 1 and 2, and x1 = 849 and x2 = 910 successes were observed.
a. Find a 99% confidence interval for the difference (p1 - p2) in the two population proportions. What does "99% confidence" mean?
b. Based on the confidence interval in part a, can you conclude that there is a difference in the two binomial proportions? Explain.