Chapter 7 - Confidence Intervals and Sample - 7-3 Confidence Intervals and Sample Size for Proportions - Extending the Concepts - Page 397: 22

n = 1015, z_α/2 = , E=0.03, p̂ =0.68 , q̂ = 0.32 n = p̂q̂ ($ \frac{z_α/2}{E}^{2}$) 1015=(0.68)(0.32)($ \frac{z_α/2}{0.03}^{2}$) $z_α/_2 $=2.05 From the table, When $z_α/_2 $=2.05, 1- α/2=0.9798 $α/2$ =0.0202 α = 0.0404 Confidence interval = 1-0.0404 = 0.9596 = 95.96%