Bar Graphs, Pie Charts, and more

The first thing we will discuss is the area principle, which basically states that each unit in our sample should be equally represented with area on a graph. This way, we can see that a larger area means more units in that category.

A bar chart is a graphical representation of categorical data.

We will discuss both a basic bar chart and a segmented bar chart.

For a basic bar chart, the x-axis is the categories for your variable, and the y-axis is either the frequency, or relative frequency.

See the video for a detailed look at making a bar chart.

For a basic bar chart, you can only use one variable. We get this information from a frequency distribution. But for a segmented bar chart, you can use two variables. This is what is used for a contingency table.

Please refer to the second video for a detailed explanation of making a segmented bar chart.

The third graph discussed in this powerpoint is a pie chart.

This is represented by a circle, marked off by lines radiating from the center of the circle.

Each piece of the pie represents a category.

The second video shows you how to make a pie chart.

Make sure you give every chart a title and axis label.

This ensures that whoever is looking at your graph can understand it without having to reference anything else.