JEE Main 2013 (Online) 22nd AprilQuestion 1
Mean of $5$ observations is $7$. If four of these observations are $6,7,8,10$ and one is missing then the variance of all the five observations is :
Statistics
Solution
The missing value is $35-31=4$. Deviations from $7$: $-1,0,1,3,-3$, so the variance is $\frac{1+0+1+9+9}5=4$.