Question

The mean of the squares of first n natural numbers is

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

Answer 1

The correct option is D $\frac{1}{6}(n+1)(2n+1)$

$Mean=\frac{E{n}^2}{n}=\frac{n(n+1)(2n+1)}{6n}\frac{(n+1)(2n+1)}{6}$