Construct A $90 \%$ Confidence Interval For $\left( p _ { 1 } - p _ { 2 } \right)$

Essay

Construct a $90 \%$ confidence interval for $\left( p _ { 1 } - p _ { 2 } \right)$ when $n _ { 1 } = 400 , n _ { 2 } = 550 , \hat { p } _ { 1 } = .42$ , and $\hat { p } _ { 2 }$ $= .63$ .