Calculate variance if $\Sigma x_i^2=18000$ and $\Sigma x_i=960$, for 60 observations
Calculate variance if $\Sigma x_i^2=18000$ and $\Sigma x_i=960$, for 60 observations
44
22
32
6.63
Solution
For 60 observations it's given that $\Sigma x_i=960$ and $\Sigma x_i^2=18000$
So, the variance $=\frac{\Sigma x_i^2}{60}-\left(\frac{\Sigma x_i}{60}\right)^2=\frac{18000}{60}-\left(\frac{960}{60}\right)^2$
$
=300-(16)^2=300-256=44
$