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# How do you Make a Histogram?

TopA Histogram is a Graphical representation of data like the Bar Graph, but it is used for continuous class intervals. A Histogram consists of a Set of adjacent rectangles. It was first introduced by Karl Pearson. The total area of histogram is equal to the number of data’s. The rectangles of a Histogram are drawn so that they touch each other because the original variable is continuous. If the length of intervals on x-axis is equal to 1, then a histogram is identical to relative frequency. There can be equal width or varying width between the class intervals. Now the question is how to draw histogram. Few steps are mentioned below to draw a histogram with uniform width.
Step 1:- Draw two Perpendicular Lines meeting each other at O (i.e., origin), the horizontal line (i.e., x-axis) and the vertical line (i.e., y-axis).
Step 2:- Observations are represented on x-axis. ‘Break’ can be used on x-axis if class intervals are not starting with zero.
Step 3:- Frequency is represented on y-axis by choosing a proper scale. There should be minimum and maximum values of frequency.
Step 4:- Draw rectangular bars of width equal to class size and height equal to frequency of corresponding class intervals.

There should be no gap in between these rectangular bars. It is called Histogram with uniform width. In case where class intervals are continuous but there widths are not same then Histogram with varying class intervals is drawn.
Steps to draw a histogram with varying class intervals:-
Step 1:- Find the minimum class size of the intervals given in the frequency distribution.
Step 2:- Then find length of Rectangle for each class using the formulae-
Length of Rectangle = (Minimum Class Size/ Class Size) x Frequency of the Class
Step 3:- Draw the rectangles with class size as width and length as obtained in step 2.

With the help of these steps we can draw two types of Histograms.