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Question
Verify the following function, which can be regarded as p.m.f. for the given values of X :
| X = x | -1 | 0 | 1 |
| P(x) | -0.2 | 1 | 0.2 |
Solution
In order that given function is p.m.f. it must satisfy
(i) P (X = x) ≥ ∀x and
(ii) ΣP(X = x) = 1
In the given data P(-1) = - 0.2 < 0
Here P(X = x) ≥ 0 , ∀x is not satisfied
∴ Given function can not be regarded as p.mf.
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