Graphs in Education: Considering Sources of Error in Graphs

Saturday, July 18, 2015

Considering Sources of Error in Graphs

The topic of error is essential when teaching graphs. Error describes inaccurate data, resulting in a graph which does not match the real-life phenomena it intends to measure. Error may occur at one or more points on the graph, which may be found in one or more segments of the graph.

Graphing errors may occur when the measurement device is not accurate, or when data is not properly recorded. Not all errors may be what they seem, however. Sometimes graphs accurately portray an inaccurate performance. Is it possible to determine the source(s) of error from a graph alone?

Consider the following two graphs, excerpted from the book series The Science of Home Construction from Schottenbauer Publishing:

Discussion Questions

Does either graph contain error? Why or why not?
Does either graph show error due to the measurement device? Why or why not?
In either graph, does the real phenomena provide an unexpected contour? Why or why not?
For either graph, would changing the perspective increase/decrease the apparent error? Why or why not?
Redraw these two graphs, eliminating the likely error(s).

Schottenbauer Publishing offers over 100 books with graphs of popular topics, including sports, transportation, construction, environment, music, entertainment/toys, and physics. Free samples from these books are featured in the following free blogs, which contain graphs, videos, and discussion questions:

Blogs with Free Graphs