The Don'ts of Plotting Graphs

In newspapers, blogs, or social media there are a lot of misleading graphs that make people misunderstand the actual data. You will be going through some of these examples and learn how to avoid them.

Manipulating the Axis

Imagine you have three students with three different scores from an exam. Now, you have to plot their scores on a bar chart. There are two ways to do this: the misleading way, and the right way:

Figure 4.23: Chart A (starts from 80) and Chart B (starts from 0)

Looking at Chart A, it will be interpreted that the score of student A is about 10 times higher than student B and student C. However, that is not the case. The scores for the students are 96, 81, and 80, respectively. Chart A is misleading because the y-axis ranges from 80 to 100. The correct y-axis should range from 0 to 100, as in Chart B. This is simply because the minimum score a student can get is 0, and the maximum score a student can...