Question

Find the mean.

$$\begin{array}{cccccc}{x}_i& 10& 14& 18& 21& 25\\ f_i& 10& 15& 7& 9& 9\end{array}$$

Answer 1

$$\begin{array}{ccc}{x}_i& f_i& f_i{x}_i\\ \text{10}& \text{10}& \text{100}\\ \text{14}& \text{15}& \text{210}\\ \text{18}& \text{7}& \text{126}\\ \text{21}& \text{9}& \text{189}\\ \text{25}& \text{9}& \text{225}\end{array}$$
$\sum f_i$=50
$\sum f_i{x}_i$ = 850
Mean = $\frac{850}{50}=17$