For this problem, carry at least four digits after the decimalin your calculations. Answers may vary slightly due torounding.
A random sample of medical files is used to estimate the proportionp of all people who have blood type B.
(a) If you have no preliminary estimate for p, how manymedical files should you include in a random sample in order to be85% sure that the point estimate p̂ will be within adistance of 0.04 from p? (Round your answer up to thenearest whole number.)
medical files
(b) Answer part (a) if you use the preliminary estimate that about12 out of 90 people have blood type B.
medical files
