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 stratified random sample, and three stratification schemes have been proposed. scheme 1: stratify adult residents into four strata based on the first 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 five strata by randomly assigning residents into one of the five strata. which of the three stratification schemes would be best in this situation