Question

A bag contains 1 red and 3 white balls. Find the probability distribution of the number of red balls if 2 balls are drawn at random from the bag one-by-one without replacement.

Answer 1

Let X be the random variable defined as the number of red balls.

Then X = 0, 1

P(X = 0) = `3/4 xx 2/3 = 6/12 = 1/2`

P(X = 1) = `1/4 xx 3/3 + 3/4 xx 1/3 = 6/12 = 1/2`

Probability Distribution Table:

X	0	1
P(X)	`1/2`	`1/2`