Question:
The mean and variance of 20 observations are found to be 10 and 4 , respectively. On rechecking, it was found that an observation 9 was incorrect and the correct observation was 11. Then the correct variance is
Correct Option: 1
Solution:
$\frac{\sum x_{i}}{20}=10 \Rightarrow \Sigma x_{i}=200$ .........(i)
