A researcher wishes to estimate. with 95% aziontidenoe1 the population proportion of adults who think Congress is doing a good or excellent job. Her estimate must be accurate within 1% of the true proportion. {a} No preliminary estimate is available. Find the minimum sample size needed. to} Find the minimum sample size needed, using a prior study that found that 28% of the respondents said they think Congress is doing a good or excellent job. (0) Compare the results from parts (a) and (b). {a} What is the minimum sample size needed assuming that no prior information is available? n ~= (Round up to the nearest whole number as needed.) {b} What is the minimum sample size needed using a prior study thatfound that 23% ofthe respondents said the}.I think Congress is doing a good or exoellentjob? n = {Round up to the nearest whole number as needed.) (o) How do the results from (a) and (b) compare? 0 A. Having an estimate of the population proportion has no effect on the minimum sample size needed. 0 B. Having an estimate of the population proportion raises the minimum sample size needed. 0 0. Having an estimate of the population proportion reduces the minimum sample size needed