Suppose that you were asked to help design a survey of adult city residents in order to estimate the proportion that would support a sales tax increase. The plan is to use a strati?ed random sample, and three strati?cation schemes have been proposed.
Scheme 1: Stratify adult residents into four strata based on the ?rst letter of their last name (A-G, H-N, O-T, U-Z)
Scheme 2: Stratify adult residents into three strata: college students, nonstudents who work full time, nonstudents who do not work full time.
Scheme 3: Stratify adult residents into ?ve strata by randomly assigning residents into one of the ?ve strata. Which of the three strati?cation schemes would be best in this situation? Explain.