Independent random samples of n1 = 500 and n2 = 500 observations were selected from binomial populations 1 and 2, and x1 = 120 and x2 = 147 successes were observed.
a. What is the best point estimator for the difference (p1 - p2) in the two binomial proportions?
b. Calculate the approximate standard error for the statistic used in part a.
c. What is the margin of error for this point estimate?