Question

The children in a class did a survey of the number of siblings (brothers and sisters) each of them had. The results are recorded in the following table. Calculate the mean number of siblings.

• A. 2
• B. 2.6
• C. 2.5
• D. 3

Answer 1

The correct option is B 2.6

$$\begin{array}{ccc}Number\left(x_i\right)& f_i& f_i{x}_i\\ ofsiblings& & \\ \text{0}& \text{3}& \text{0}\\ \text{1}& \text{6}& \text{6}\\ \text{2}& \text{8}& \text{16}\\ \text{3}& \text{5}& \text{15}\\ \text{4}& \text{4}& \text{16}\\ \text{5}& \text{2}& \text{10}\\ \text{6}& \text{1}& \text{6}\\ \text{7}& \text{0}& \text{0}\\ \text{8}& \text{0}& \text{0}\\ \text{9}& \text{1}& \text{9}\\ & \sum f_i=30& \sum f_i{x}_i=78\end{array}$$
$Mean=\frac{\sum f_i{x}_i}{\sum f_i}=\frac{78}{30}=2.6$