Data and Graphs — Grades 4-5 is a unit that covers common statistical graphs and some related topics. It is a worktext, containing both the “text” (instruction) and the “work” (exercises and problems).
The unit starts with bar graphs, histograms, and various kinds of line graphs.
The goals for the study of bar graphs and line graphs are listed here. The student should learn to:
1. Read bar graphs, including double bar graphs, and answer questions about already plotted data.
2. Draw bar graphs and histograms from a given set of data.
In order to make histograms, it is necessary to understand how to group the data into categories (“bins”). The lesson Making Histograms explains the method we use to make categories if the numerical data is not already categorized.
Toward the end of the unit, we study average (also called the mean) and mode, and how these two concepts relate to line and bar graphs. Other math curricula also introduce the median, but I decided to omit it from this unit. There is plenty of time to learn that concept later, for example in the unit Statistics, Grade 6. Introducing all three concepts at the same time tends to jumble them together and become confusing — so that many students just grasp the calculation procedures. I feel it is better initially to just introduce and contrast the two concepts of the mean and mode, in order to give the student a solid foundation.