Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level.
a. n = 500, x = 220, 99% confidence
b. 90% confidence; the sample size is 1780, of which 35% are successes
8. Use the given sample data and confidence level to construct the confidence interval estimate of the population proportion p for each problem.
a. n = 2000, x = 400, 95% confidence
b. n = 5200, x = 4821, 99% confidence