Mean

Example :

Find the mean of the set $\left\{2,5,5,6,8,8,9,11\right\}$ .

There are $8$ numbers in the set. Add them all, and then divide by $8$ .

$\begin{array}{l}\frac{2+5+5+6+8+8+9+11}{8}=\frac{54}{8}\\ =6.75\end{array}$

So, the mean is $6.75$ .