Probability Questions - Cannot seem to figure out

I have been working on this problem for a few days now and cannot seem to at least find a formula or example in my book that works. Any help would be very much appreciated, thanks!

In 2009, according to a Harris Interactive poll, 52% of American college graduates have Facebook accounts. Suppose that this result is true for the current populations.

Let x be a binomial random variable that denotes the number of American College graduates in a random sample of 15 who have Facebook accounts.

Show your work.

a) What are the possible values that x can assume?

b) Find the probability that 9 of the 15 people have a Facebook account.


TS Contributor
Look at the binomial distribution. What would be an experiment, what would be considered a success and what would be the probanility of a success?



Active Member
This is a prototypical example of using the binomial distribution. The formula is in your book in one way or another (unless you aren't reading a stats book).