Refer to Problems 14 and 15.
a. Take half the length of the confidence interval found in Problem 15(a) to obtain the margin of error for the estimate of the difference between the two population proportions. Interpret your result in words.
b. Solve part (a) by applying Formula 11.3 on page 466.
c. Obtain the common sample size that will ensure a margin of error of at most 0.03 for a 98% confidence interval without making a guess for the observed values of the sample proportions.
d. Find a 98% confidence interval for p1 − p2 if, for samples of the size determined in part (c), the sample proportions are 0.475 and 0.603, respectively.
e. Determine the margin of error for the estimate in part (d) and compare it to the required margin of error specified in part (c).