b . Margin of error = (+/- 5% ) C. Standard deviation .5 d. 90 % confidence level Sample Size : 329 n= (z-score )2 x std Dev (1-std Dev )/(margin of error )2 n= (1.645 )2 x .5 (.5)/(.05 )2 n= (3.29 x .25 )/.0025 n= 0.8225 /.0025 n = 329