If a manufacturer conducted a survey among randomly selected

If a manufacturer conducted a survey among randomly selected target market households and wanted to be 95% confident that the difference between the sample estimate and the actual market share for its new product was no more than + or - 2%, what sample size would be needed?

Compute Sample Size ( n ) = n=(Z/E)^2*p*(1-p)
Z a/2 at 0.05 is = 1.96
Sample Proportion = 0.05
ME = 0.02
n = ( 1.96 / 0.02 )^2 * 0.05*0.95
= 456.19 ~ 457