JEE Main 2019 (Online) 10th January Evening ShiftQuestion 1
If the mean and standard deviation of $5$ observations $x_1,x_2,x_3,x_4,x_5$ are $10$ and $3$, respectively, then the variance of $6$ observations $x_1,x_2,\ldots,x_5$ and $-50$ is equal to :
Statistics
Solution
$\sum x=50$, $\sum x^2=5(9+100)=545$. With $-50$: sum $0$, $\sum x^2=3045$, variance $=\frac{3045}6=507.5$.