As recently as 2008, 70% of users of social networking sites such as Facebook were 35 years old or younger. Now the age distribution is much more spread out. Table 7.10 shows the age distribution of 975 users of social networking sites from a survey reported in June 2011.

Table 7.10

(a) Test an assumption that users are equally likely to be in each of the five age groups listed. Show all details of the test.
(b) Which age group contributes the largest amount to the sum for the χ² test statistic? For this age group, is the observed count smaller or larger than the expected count?

Transcribed Image Text:

23-35 312 50-65 65+ 59 Age Frequency 18–22 156 36–49 253 195