Question

Prepare a continuous grouped frequency distribution from the following data. Also find the size of class intervals.

Answer 1

Step 1. Determine the size of class intervals.

Difference between two mid points is $15-5=10$.

It depicts that the width of class interval is $10$

Consider a as the lower limit of the first class interval

So the upper limit $=a+10$

Mid class of the first class interval $=5$

$\begin{array}{rcl}\mathrm{Mid}\mathrm{value}& =& \frac{(\mathrm{Lower}\mathrm{limit}+\mathrm{Upper}\mathrm{limit})}{2}\\ 5& =& \frac{a+a+10}{2}\\ 10& =& 2a+10\\ a& =& 0\end{array}$

First class interval is $0-10$

The continuous grouped frequency distribution table is

Hence, the size of class intervals is $10$.