SOLUTION: suppose that a student needs to buy 6 books for her clas. the number of books that she will be able to find used is a binomial random variable X with n = 6 and p = .30. In other wo

Algebra ->  Probability-and-statistics -> SOLUTION: suppose that a student needs to buy 6 books for her clas. the number of books that she will be able to find used is a binomial random variable X with n = 6 and p = .30. In other wo      Log On


   

Question 387871: suppose that a student needs to buy 6 books for her clas. the number of books that she will be able to find used is a binomial random variable X with n = 6 and p = .30. In other words the probability that she will find any given book is .30, and is independent from one book to the next.
What is the probability that she will find exactly 2 books?
What is the variance for the number of used books she will find V(X)?
Answer by user_dude2008(1862) About Me  (Show Source):
You can put this solution on YOUR website!
What is the probability that she will find exactly 2 books?

(6 choose 2)*(0.3)^2*(1-0.3)^(6-2) = 0.324135


What is the variance for the number of used books she will find V(X)?

variance is V(X)=np(1-p)