# What is the variance of {3,6,7,8,9}?

variance of $\left\{3 , 6 , 7 , 8 , 9\right\} = 5.3$
The formula for variance, ${s}^{2}$, is
$\textcolor{w h i t e}{\text{XXX}} {s}^{2} = \frac{\sum \left({x}_{i} - \overline{x}\right)}{n - 1}$
where $\overline{x}$ is the mean of the sample set
$\textcolor{w h i t e}{\text{XXX}}$in this case the mean of $\left\{3 , 6 , 7 , 8 , 9\right\}$ is $\frac{\sum {x}_{i}}{5} = 6.6$