Question

Second central moment (Variance) for the first $n$ natural numbers is ____.

• A. $\frac{n(n+1)}{2}$
• B. $\frac{n(n+1)(2n+1)}{6}$
• C. $\frac{n^2+1}{12}$
• D. $\frac{n^2-1}{12}$

Hint:

Memorize variance of first $n$ natural numbers: $\frac{n^2-1}{12}$.

Answer 1

The Correct Option is D