GATE 2020 PI – Question 15

Engineering Mathematics · Probability and Statistics · 1 mark · Multiple choice

A random variable has mean5 and variance1. Find E[X²].

Show answer and explanation

Correct answer: (C) 26

Explanation

By definition Var(X)=E[X²]−(E[X])². Rearranging gives E[X²]=1+5²=26, C. The square of the mean alone omits the variance contribution.

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