The fruit fly Drosophila melanogaster normally has a gray color. However, because of mutation a good portion of them are black. A biologist eager to learn about the effect of mutation wants to collect a random sample to estimate the proportion of black fruit flies of this type within 1% error with 95% confidence.
(a) How many individual flies should the researcher capture if there is no information on the population proportion of black flies?
(b) Suppose the researcher has the initial estimate that 25% of the fruit fly Drosophila melanogaster have been affected by this mutation. What is the sample size?