Using a misleading graph leads to the wrong conclusions.
See solution.
Practice makes perfect
We are asked to give an example of a bar graph that is misleading. In other words we want to show a bar graph that leads us to the wrong conclusions. Let's suppose that we have a table of data values describing the number of t-shirts sold by color.
Color
Number of T-Shirts Sold
Pink
36
Blue
34
Black
31
White
35
Yellow
33
Green
34
Now, let's assume that we want to display our data. Because we have multiple categories — colors — we can use a bar graph. We can see that all data values are greater than 30 so we could think that our vertical axis can begin at 30.
Looking at the graph, it seems like the differences between the colors are big and very few people buy black t-shirts. However, this conclusion is only an effect of using a break on one of the axis. By doing that we ended up with a misleading graph. Let's make another graph but this time with the correct y-axis.
Now the differences between the bars are not that big and we can see that in fact the number of t-shirts sold is similar for all colors. Remember that we should always try to make a non-misleading graph because analyzing a misleading graph leads us to the wrong conclusions.
