Question: A Phoenix wealth management/harris interactive survey of 1500 people w/net worth of $1 million or more provided a variety of stats on wealthy people. The previous 3-year period had been bad for stock.

(a) Survey reports that 53% of the respondents lost 25% or more of their portfolio value over the past 3 years. Develop a 95% confidence interval for the proportion of wealthy people who lost 25% or more of their portfolio over the past 3 years.

(b) 31% of the respondents feel they have to save more for retirement to make up for the lost. Develop a 95% confidence interval for the population proportion.

(c) Five % of respondents gave $25,000 or more to charity over previous year. Develop 95% confidence interval for the proportion who gave $25,000 or more to charity.

(d) Compare the margin of error for the interval estimates in part(d),(b), and (c).how is the margin of error related to p(bar)? When the same sample is being used to estimate a variety of proportions, which of the proportions should be used to choose the planning value p*? Why do you think p* = .50 is often used in cases?