Cuemath
Cuemath: Bar Graphs
A comprehensive guide for learning all about bar graphs with definitions, solved examples, and practice questions.
Texas A&M University
Wtamu Virtual Math Lab: Beginning Algebra: Reading Graphs
A good introduction to reading bar, line, and double line graphs, and drawing and reading Venn diagrams. Contains definitions and examples of these types of charts and graphs as well as practice exercises that ask you to answer questions...
Other
Stat Soft: Statistics Glossary
Dozens of statistical terms are defined and illustrated in this glossary.