A survey of 777 teenagers between the ages of 13 and 18 conducted by JA Worldwide/Deloitte & Touche USA LLP found that 69% agree that people who practice good business ethics are more successful than those who do not.
a. Calculate the 90% confidence interval estimate for the true population proportion, p , given the survey information.
b. What is the largest possible sample size needed to estimate the true population proportion, p , within a margin of error of ± 0.02 with a confidence level of 95% if there was no prior knowledge concerning the proportion of respondents who would agree with the survey’s question?
c. If the survey in part a had a margin of error of ± 0.04 percentage points, determine the level of confidence that was used in estimating the population proportion if there was no prior knowledge concerning the percentage of teenagers who would respond as they did.