A researcher wishes to? estimate,90?% ?confidence, the population proportion of adults who say chocolate is their favorite ice cream flavor. Her estimate must be accurate within 1% 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 their favorite flavor of ice cream is chocolate.
?(c) Compare the results from parts? (a) and? (b).