A university dean is interested in determining the proportio

A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. If the dean wanted to estimate the proportion of all students receiving financial aid to within 1% with 90% reliability, how many students would need to be sampled?

Solution

p=118/200 =0.59 E=0.03, a=0.01, Z(0.005)=2.58 (check standard normal table) n=(Z/E)^2 * p*(1-p) =(2.58/0.03)^2*0.59*(1-0.59) =1789.092 Take n=1790