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
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X or x_{i}

0

1

2

3

P(X) or p_{i}

_{}

_{}

_{}

_{}

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