Question

The variance of first $20$ natural numbers is

• A. $133/4$
• B. $279/12$
• C. $133/2$
• D. $399/4$

Answer 1

The correct option is A $133/4$

The variance of first $n$ natural numbers is $\frac{n^2-1}{12}$
For the first $20$ natural number,
Vairance $=\frac{{20}^2-1}{12}=\frac{133}{4}$