If n=160 and phat=0.95, construct a 95% confidence interval

Answer 1

p* ± z^*(sqrt(p*(1-p*)/n) 

 

z^* is the upper (1 - C)/2 critical value, for 95% z^* = 1.96 since Z(1.96) = 0.9750 

 

The confidence interval is 

 

0.95 ± 1.96(sqrt(0.95*0.05/160)

0.95  ± 1.96(0.01723)

0.95  ± 0.034

 

(0.916,0.984)