Posted by **osman** on Friday, March 1, 2013 at 8:14am.

There are 9 tennis balls in a box, of which only 5 have not previously

been used. Four of the balls are randomly chosen from the box. Let be the

number of new balls among the selected ones.

(a) Find the probability distribution of :

(b) Evaluate the expectation E:

(c) Evaluate the variance V ar