the problem is to find the sample size needed. I'm given +or- 0.025 at the 95% confidence level and 58% of the population.
so the answer is given as follows:
a/2=0.025 z(a/2)=-1.96 [z(a/2)]^2=3.84 pie = 0.58 1-pie=0.42
E=0.05 the answer is n=374.
I don't understand how to use this information to get the answer. All I've been able to find is that E=(z*stdev/sqrt n) which is n=(z(a/2)*stdev/E)^2.
What am I doing wrong and explain please.