In the survey of 2255 US adults described in Exercise 6.39, we also learn that 970 of the respondents use the social networking site Facebook. Of the 970 Facebook users, the survey shows that on an average day: 

• 15% update their status

• 22% comment on another’s post or status

• 20% comment on another user’s photo

• 26% ‘‘like” another user’s content

• 10% send another user a private message.

(a) For each of the bulleted activities, find a 95% confidence interval for the proportion of Facebook users engaging in that activity on an average day.

(b) Is it plausible that the proportion commenting on another’s post or status is the same as the proportion updating their status? Justify your answer.  

Exercise 6.39

In a survey of 2255 randomly selected US adults (age 18 or older), 1787 of them use the Internet regularly. Of the Internet users, 1054 use a social networking site.