Measures of Dispersion (Part 1)

Posted on April 21, 2020 by user

Measures of Dispersion (Part 1)

7.2a Range

(A) Range of Ungrouped Data

Example 1:
Find the range for the set of data 2, 4, 7, 10, 13, 16 and 18.

Solution:

Range = largest value – smallest value

= 18 – 2

= 16

(B) Range of Grouped Data (with Class Interval)

Example 2:

The grouped frequency distribution was obtained from 100 students regarding the scores in their test shown as below.

Find the range of the data.

Solution:

\begin{array}{l} Range \\ = midpoint of the highest class - midpoint of the lowest class \\ Range = \frac{35 + 39}{2} - \frac{5 + 9}{2} \\ = 37 - 7 \\ = 30 \end{array}