MainStayInvestments is oneof theinvestment vehicles used byNewYorkLifeInvestmentManagement (NYLIM).Therespondents to asurveyconducted byNYLIM and who are agedbetween 26and 82 indicated that 66% of seniors, 61 %of babyboomers, and 58%of GenerationX expectIndividual Retirement Accounts (IRAs)to betheirprimary sourceof income in retirement. The margin oferror wasgivenas±5percentagepoints.
a. Calculate a95%confidence intervalfor theproportion of seniors who expectIRAs to betheir primarysourceof income in retirement.
b. Although the samplesizeforthe entiresurveywaslisted, the samplesizeforeach of thethreegenerations was notgiven. Assumingthe confidence level was 95%, determinethesamplesizeforeach of the threegenerations.