Title: Steps to construct Histograms - Return here if you have questions on the process.
Course: Introduction to Statistics

Histograms are a very common way to display data.  Very similar to a bar graph (which is used for categorical data), but the bars may touch each other depending on the data.

To make a histogram:

You will need a vertical axis to represent the frequency and a horizontal axis to represent the values in your set of data.  It is not a line plot where you simply put marks (dot or X) above the values.

The bars generally contain multiple values.  A general rule in setting up your horizontal axis is to find the range (maximum value - minimum value) and divide by 7.  We then round that value off to the nearest integer to determine our bin width.  Hopefully this will allow us a good view of the data.

Occasionally you will need to make adjustments to your bin widths (spread of the bars) to get a better view.  The values that go into each bar include the left side, but not the right.  For example, if a bar starts at 2 and ends at 5, it will include all values greater than or equal to 2 and at the same time less than 5.  Values of 5 will move into the next bar.