# describe precisely how this interval was obtained using the calculator method

For Chapter 8, Facebook claims that the average number of Facebook friends per Facebook user is 190; however, whenever we collect a significant amount of data we find that users have, on average, significantly more than 190 friends. So we want to test the claim that the population mean number of Facebook friends is actually more than 190. The real test will come in the next chapter, where we do significance (hypotheses) tests, but here, we’ll look at the confidence interval and see what that tells us.

Using your Facebook account, check your profile page to see how many friends you have. Then get a complete listing of your friends from Facebook by clicking on the Friends area of your profile page. Using the random number generator on your calculator, find ten random integers between 1 and the total number of Facebook friends you have. (For example, if you have 542 Facebook friends, do MATH > PRB > randInt(1,542,10) to get ten random integers between 1 and 542.)

For each of these random integers, find the friend that corresponds to that number. (For example, if my first random integer was 170, I would find my 170th friend and record the number of friends he or she has, and repeat this process for the remaining nine friends.)

In your post, tell us:

-How many total Facebook friends you have (I have 660)

-The ten random integers you came up with,

-The number of Facebook friends each of those ten friends has,

-The sample mean of these ten friends’ numbers of friends,

-The 95% confidence interval for the average number of Facebook friends a Facebook user has based on your data, being sure to describe precisely how this interval was obtained using the calculator method, and

-Exactly how we should interpret this confidence interval in the context of the variable and the population.

For all deep dives and projects, rounded final answers should contain at least three significant digits, and numbers used to compute final answers should contain at least four significant digits. (Note that answers that are exact and don’t need to be rounded need not have digits added. This guideline is only for answers that are being rounded.)

I have 660 friends on my personal Facebook page.