Question

The mean of $100$ observations is $50$ and their standard deviation is $5$. The sum of all squares of all the observations is

• A. $50000$
• B. $250000$
• C. $252500$
• D. $255000$

Answer 1

Answer: (C)

$252500$

Answer 2

\Sigma x_{i}^{2}=n\left\\{\sigma^{2}+\left(\bar{x}\right)^{2}\right\\}=100\left(5^{2}+50^{2}\right)=252500