(b) With 99% confidence, what is the possible error if the proportion is estimated
to be 12/100 0.12?
9.38 In a public opinion poll such as the one described in Example 9.21, determine the
minimum sample size needed for the poll so that with 95% confidence the sample
means will be within 0.05 of the true proportion. [Hint: use the fact that
X(1 X) 1/4 in Equation (9.153).]
314 Fundamentals of Probability and Statistics for Engineers