Scatter and bubble charts show how values are spread over each variable's range. The textbook's example: from one scatter chart you can see that only 2 of 51 cities average more than 80 inches of snowfall a year.

Column and bar charts show a distribution over discrete categories or time periods. Over time, use a column chart rather than a bar chart, because time reads more naturally left to right.

A choropleth map shows a distribution over geographic space.