Scatter and Jittered Scatter Plots
A scatter plot is “a type of diagram using Cartesian coordinates to display values for two variables for a set of data. The data is displayed as a collection of points, each having the value of one variable determining the position on the horizontal axis and the value of the other variable determining the position on the vertical axis” (Wikipedia). Scatter plots are often used to visualize all individual data points, not just mean values as in line plots. In many circumstances, scatter plots might be preferred to line plots because they allow us to visualize all data points, including outliers. A scatter plot is a good example of letting the data speak for themselves, one important principle for data visualization and exploration (Tufte, 1983, 1997, 2006).