State if the following is not the probability mass function of a random variable. Give reasons for your answer. X 0 -1 -2 P(X) 0.3 0.4 0.3 - Mathematics and Statistics

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Sum

State if the following is not the probability mass function of a random variable. Give reasons for your answer.

0 -1 -2
P(X) 0.3 0.4 0.3
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Solution

P.m.f. of random variable should satisfy the following conditions :

(a) 0 ≤ pi ≤ 1

(b) ∑pi = 1.

0 -1 -2
P(X) 0.3 0.4 0.3

(a)  Here 0 ≤ pi ≤ 1

(b) ∑pi = 0.3 + 0.4 + 0.3 = 1

Hence, P(X) can be regarded as p.m.f. of the random variable X.

Concept: Probability Distribution of Discrete Random Variables
  Is there an error in this question or solution?
Chapter 7: Probability Distributions - Exercise 7.1 [Page 232]

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