Test Index

Probability

Question : 35 of 127

Marks: +1, -0

{x}

is given by

Solution:

Concept:

Variance is the expected value of the squared deviation of a random variable from its mean.

Explanation:

Option A:

E(x-μ)^2

means

E[(x-μ)^2]

, where

μ = E(x)

Option B:

E[x-E(x)]^2

also means

E[(x-E(x))^2]

, which is the same as option A.

Option C:

E(x^2-μ) = E(x^2) - μ

is not variance; variance is

E(x^2) - [E(x)]^2

Thus both A and B are correct definitions of variance.

Answer:

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