A researcher wishes to estimate, with 95% confidence, the population proportion of adults who are confident with their country’s banking system. His estimate must be accurate within 4% of the population proportion.
(a) What is the minimum sample size needed assuming that no prior information is available?
(b)What is the minimum sample size needed using a prior study that found that 36% of the respondents said they are confident with their country’s banking system?
(2) How do the results from (a) and (b) compare?
a) Having an estimate of the population proportion reduces the minimum sample size needed.
b) Having an estimate of the population proportion has no effect on the minimum sample size needed.
c) Having an estimate of the population proportion raises the minimum sample size needed.