5.34 Number of friends on Facebook. To commemorate Facebook’s 10-year milestone, Pew Research reported several facts about Facebook obtained from its Internet Project survey. One was that the average adult user of Facebook has 338 friends. This population distribution takes only integer values, so it is certainly not Normal. It is also highly skewed to the right, with a reported median of 200 friends.8 Suppose that σ = 380 and you take an SRS of 80 adult Facebook users.

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    (a) For your sample, what are the mean and standard deviation of , the mean number of friends per adult user?

  2. (b) Use the central limit theorem to find the probability that the average number of friends for 80 Facebook users is greater than 350.

  3. (c) What are the mean and standard deviation of the total number of friends in your sample?

  4. (d) What is the probability that the total number of friends among your sample of 80 Facebook users is greater than 28,000?