- Histogram is the most properly and widely used methods of graphical representations.
- Histogram is a two dimensional graphical representation of a continuous frequency distribution.
- In a histogram the area of rectangular are proportional to the frequencies.
Class intervals are marked on the x – axis and frequencies on the Y – axis. Class intervals must be exclusive. IF the class intervals are in inclusive form, they are to be converted into exclusive form. Rectangles of width equal to class interval and length equal to frequencies re drawn.
Example for Histogram:
CI | 25-29 | 30-35 | 36-40 | 41-50 | 51-56 | 57-60 |
f | 10 | 24 | 15 | 20 | 12 | 16 |
Solution:
CI | 24.5-29 | 29.5-35.5 | 35.5 – 40.5 | 40.5-50.5 | 50.5-56.5 | 56.5-60.5 |
f | 10 | 24 | 15 | 20 | 12 | 16 |
class width | 5 | 6 | 5 | 10 | 6 | 4 |
length of the rectangles | 10 | 20 | 15 | 10 | 10 | 20 |