From a lot containing 25 items, 5 of which are defective, 4 are chosen at random. Let X be the number of defectives found. Obtain the probability distribution of X if the items are chosen without replacement.
X represents the number of defective items drawn.
∴ X can take values 0,1,2 or 3
∵ there are total 25 items (20 good+5 defectives) items
n(S) = total possible ways of selecting 5 items = 
P(X = 0) = P(selecting no defective item) = 
P(X = 1) = P(selecting 1 defective item and 3 good items)
= 
P(X = 2) = P(selecting 2 defective items and 2 good items)
= 
P(X = 3) = P(selecting 3 defective items and 1 good item)
= 
P(X = 4) = P(selecting 4 defective items and no good item)
= 
Now we have pi and xi.
Following table represents probability distribution of X :
