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Let the p.m.f. of a random variable X be...

Let the p.m.f. of a random variable X be -
` P(x) = (3 -x)/10 " for " x = - 1, 0, 1, 2`
= 0 otherwise
Then E(X) is ………… .

A

1

B

2

C

0

D

`-1`

Text Solution

Verified by Experts

The correct Answer is:
C
`E(x) = sum _(xi) * P(x_(i))`
` =(-1) * P (-1) + 0 * P(0) + 1 * P(1) + 2 * P(2)`
` = (-1) *(3-(-1))/10 + 0 +1*(3-1)/10 + 2 * (3-2)/10`
` = (-1) * 4/10 + 2/10 + 2/10`
= 0
Hence, the correct answer from the given alternatives is (c) .
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