Question

What is the mean of the following data?
$$\begin{array}{cc}\text{Value}& \text{Frequency}\\ 0-20& 2\\ 20-40& 3\\ 60-80& 4\\ 80-100& 1\end{array}$$

• A. 37
• B. 65
• C. 48
• D. 45

Answer 1

The correct option is C 48

$$\begin{array}{ccc}\text{Value}& \text{Frequency}& x_i\\ 0-20& 2& 10\\ 20-40& 3& 30\\ 60-80& 4& 70\\ 80-100& 1& 90\end{array}$$

$\begin{array}{ccc}\mathrm{Mean}& =& \frac{\sum _{}^{}{f}_i{x}_i}{\underset{}{\overset{}{\sum x_i}}}\\ & =& \frac{10\times 2+30\times 3+70\times 4+90\times 1}{10}\\ & =& \frac{480}{10}\\ & =& 48\end{array}$