Question

The mean of the following distribution is:
$\begin{array}{ccccc}{\text{x}}_i& 10& 13& 16& 19\\ {\text{f}}_i& 2& 5& 7& 6\end{array}$

• A. 15.2
• B. 15.35
• C. 15.55
• D. 16

Answer 1

The correct option is C

15.55

We know that,
Average or mean value of a given number of observations is the sum of all the observations divided by the total number of observations.

$\Rightarrow \text{Mean}=\frac{\sum x_i{f}_i}{\sum f_i}$

Now,
$\sum x_i$$f_i=20+65+112+114=311$

$\sum f_i=20$

So,
$\text{Mean}=\frac{\sum x_i{f}_i}{\sum f_i}=\frac{311}{20}=15.55$