A report summarizes data from a survey of a representative sample of 1,449 adult Americans. The sample
included 221 people of age 18 to 29, 796 people of age 30 to 64, and 432 people of age 65 and older. The
following statements are based on the survey data.

23% of adult Americans use Twitter
42% of Americans between the ages of 18 and 29 use Twitter
7% of Americans age 65 and older use Twitter.

(a) What is the population of interest?

all Americans who use Twitter
all Americans
adult Americans
adults who use Twitter
adult Americans who use Twitter

(b) What population characteristics are being estimated?

the percentage of the population of interest who are adults
the total number of people in the population of interest who have used Twitter
the percentage of the population of interest who use Twitter
the total number of people in the population of interest
the percentage of the population of interest who are American

(c) Do you think that the actual percentage of all adult Americans who use Twitter is exactly 23%?
Explain why or why not.

Yes. This percentage is a population characteristic, meaning it describes the total population
of interest.
No. The size of the sample this estimate was based on is very small.
No. Subsequent samples may yield different estimates for this percentage.
Yes. This estimate was based on a representative sample of the population of interest.