Confidence Intervals

Question

In a Harris Poll of 412 HR professionals, 85.3% said that the job applicants appearance is most important for a good impression. Construct a 94% Confidence Interval for the True population proportion of all HR professionals who believe this. 

Answer 1

p+-z*sqrt(p(1-p)/n)Confidence Interval of p

pˆ±z∗sqrt(p(1-p)/n)

 

.853 (+ or -) 1.88sqrt(.853(.147)/412)

 

 

.853  ±  .033

 

(.82 , .886)