About 71% of young adult Internet users ( ages 18 to 29) use social- networking sites. Suppose that a sample survey contacts an SRS of 1500 young adult Internet users and calculates the proportion p ˆ in this sample who use social-networking sites. Solution Sol) n=1500 and p=0.71 1) P hat =0.71 2) Mean=np =0.71*1500=1065 3) standard deviation of p hat =sqrt(pq/n)= 0.0117.