According to the Retirement Confidence Survey, in 2015, 36% of individuals expected to begin retirement after the age of 65 (source: 2015 RCS Fact Sheet # 2, Expectations about retirement, www.ebri.org/).

Suppose a recent random sample of 90 households in the greater Miami area was taken and respondents were asked whether they plan to retire after the age of 65.

The results are in the file RetireAfter65.

a. Based on the random sample of Miami households, what is the best point estimate for the proportion of all Miami respondents who expect to retire after age 65?

b. Construct a 99% confidence interval estimate for the true population proportion of Miami respondents who expect to retire after age 65.

c. If the sponsors of the Miami study found that the margin of error was too high, what could they do to reduce it if they were not willing to change the level of confidence?