How do Millennials respond to content marketing? According to a NewsCred study, 31% of Millennials are more likely to buy if the brand delivers interesting content that teaches them something. (Data extracted from "Build brand loyalty with millennials with meaningful content," February 25, 2015, bit.ly/1BbXLPP.)

a. To conduct a follow-up study that would provide 95% confidence that the point estimate is correct to within ± 0.04 of the population proportion, how large a sample size is required?

b. To conduct a follow-up study that would provide 99% confidence that the point estimate is correct to within ± 0.04 of the population proportion, how many people need to be sampled?

c. To conduct a follow-up study that would provide 95% confidence that the point estimate is correct to within ± 0.02 of the population proportion, how large a sample size is required?

d. To conduct a follow-up study that would provide 99% confidence that the point estimate is correct to within ± 0.02 of the population proportion, how many people need to be sampled?

e. Discuss the effects on sample size requirements of changing the desired confidence level and the acceptable sampling error.