s researcher wishes to estimate with 90% confidence the population proportion of adults who are confident with their country banking system. his estimate must be accurate within 2% of the population proportion.
(a) no preliminary estimate is available. find the minimum sample size needed
(b) find the minimum sample size needed using a prior study that found that 32% of the respondents said that they are confident with their country’s banking system
(c) compare the results from parts (a) and (b)