# Given X ~ B(n, P) if p = 0.6 and E(X) = 6, find n and Var(X). - Mathematics and Statistics

Sum

Given X ~ B(n, P) if p = 0.6 and E(X) = 6, find n and Var(X).

#### Solution

Given: p = 0.6 and  E(X) = 6

E(X) = np

∴ 6 = n × 0.6

n = 6/0.6 = 10

Now, q = 1 - p = 1 - 0.6 = 0.4

∴ Var(X) = npq

= 10 × 0.6 × 0.4 = 2.4

Hence, n = 10, Var(X) = 2.4

Concept: Mean of Binomial Distribution (P.M.F.)
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