Question

Calculate the arithmetic mean of the following frequency table.

$\begin{array}{cc}{x}_i& f_i\\ 1& 20\\ 2& 5\\ 3& 15\\ 4& 5\end{array}$

• A. 3
• B. 3.11
• C. 2
• D. 2.11

Answer 1

The correct option is D 2.11

Complete the given table as follows:

$\begin{array}{ccc}{x}_i& f_i& f_i{x}_i\\ 1& 20& 20\\ 2& 5& 10\\ 3& 15& 45\\ 4& 5& 20\end{array}$

$\text{Arithmetic Mean}=\frac{\sum f_i{x}_i}{\sum f_i}$
= $\frac{20+10+45+20}{45}$
= $\frac{95}{45}$
=$2.11$