Question

​ As part of the National Social Network Site Project researchers conducted two
surveys in 2017. The first survey asked a random sample of 799 U.S. teens about their
use of social media and the Internet. A second survey posed similar questions to a
random sample of 2253 U.S. adults. In these 2 studies, 80% of teens and 69% of
adults used social-networking sites. Construct and interpret a 95% confidence interval
for the difference between the proportion of all U.S. teens and adults who use
social-networking sites.

Answer 1

n1 = 799
n2 = 2253


Lower Limit =
upper Limit =
95% Confidence interval is ( 0.0763 , 0.1437 )
( 0.0763 < ( P1 - P2 ) < 0.1437 )

Since values of CI are positive, hence we can conclude that teens uses more social media and the Internet then adults.

The population difference in  proportion lies between 0.0763 and 01437.

We can also say that the population difference in proportions between teens and adults for using social media and the Internet lies between 0.0763 and 0.1437.