A bag contains 4 black and 3 red balls. Let X be the random variable of red balls. Find the mean and variance of the random variable X, if three balls drawn successfully with replacement.

Asked by Topperlearning User | 4th Jun, 2014, 01:23: PM

Expert Answer:

Let X be the random variable denoting the number of red balls. Then X can take values 0, 1, 2 & 3.

p = probability of getting a red ball = 3/7 and q = 1 – p = 4/7
 
X or xi
0
1
2
3
P(X) or pi
 

Answered by  | 4th Jun, 2014, 03:23: PM