We would like to construct a 95 confidence interval to estim

We would like to construct a 95% confidence interval to estimate the true proportion of all voters who plan to support the New Democratic Party in an upcoming provincial election. What sample size is required in order to estimate this proportion to within 0.04 with 95% confidence?

Please show steps.

Solution

Compute Sample Size ( n ) = n=(Z/E)^2*p*(1-p)
Z a/2 at 0.05 is = 1.96
Samle Proportion = 0.5
ME = 0.04
n = ( 1.96 / 0.04 )^2 * 0.5*0.5
= 600.25 ~ 601