# If X is a random variable with probability mass function - Mathematics and Statistics

If X is a random variable with probability mass function

P(x) = kx ,  x=1,2,3

= 0 ,     otherwise

then , k=..............

(a) 1/5

(b) 1/4

(c) 1/6

(d) 2/3

#### Solution

(c)

 x 1 2 3 P(x) k 2k 3k

Since, the function is a p.m.f.

∴ ∑P(xi) = 1
∴ k + 2k + 3k = 1
∴ k = 1/6

Concept: Probability Distribution - Probability Mass Function (P.M.F.)
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