### Theory:

The frequency distribution of data can be represented in numerous ways. The graphical representation depends on the data itself.

Let us recall the two main divisions of data.

Ungrouped data:
When the data collected is a whole or exact measurement, it is an ungrouped data or discrete data.
Grouped data:
A grouped or continuous data is any value between a minimum value and a maximum value. In other words, continuous data will have values from a particular range. This type of data can be tabulated in the form of a frequency distribution table.
Depending upon the classification of data, graphical representation may vary.

Let us look at a few of them.

We will discuss histograms and frequency polygons in detail in the upcoming sections.

Let us now get introduced to histograms.
Histograms
Histograms are one way of graphically representing a grouped data; that is, histograms represent continuous data.

Histograms are made of a set of rectangles. $$X$$-axis will have the different ranges of continuous data, and $$Y$$-axis will have the frequency.

An example of a histogram is given below.

Important!
What is the difference between a bar graph and a histogram?

Bar graphs are used to represent discontinuous data. In other words, there are gaps between two frequency rectangles in a bar graph; while histograms are used to represent continuous data, and there are no gaps between two frequency rectangles.