# Gas station without pumps

## 2012 October 13

### When is a line graph not a line graph?

Filed under: Uncategorized — gasstationwithoutpumps @ 21:39
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I recently discovered that elementary school teachers have taken to calling histograms “line plots”, and that this definition has gotten quite widespread:

A line plot is a graph that shows frequency of data along a number line. It is best to use a line plot when comparing fewer then 25 numbers. It is a quick, simple way to organize data. [http://ellerbruch.nmu.edu/classes/cs255w03/cs255students/nsovey/p5/p5.html]

A line plot shows data on a number line with x or other marks to show frequency. [http://www.icoachmath.com/math_dictionary/Line_Plot.html]

A line plot is a graph that shows frequency of data along a number line. It is best to use a line plot when comparing fewer than 25 numbers. It is a quick, simple way to organize data. [http://www.mathplanet.com/education/algebra-2/equations-and-inequalities/line-plots-and-stem-and-leaf-plots]

This page contains worksheets with line plots, a type of graph that shows frequency of data along a number line. [http://www.superteacherworksheets.com/line-plots.html]

Of course, no one outside the elementary school teachers uses that term, which is confusingly similar to the standard term “line graphs”.  Even the superteacherworksheets site acknowledges the terrible confusion that the “line plot” term generates:

Line Graph Worksheets Line graphs (not to be confused with line plots) have plotted points connected by straight lines.

“Line graph” is a common term, even among educators:

Line graph is a graph that uses line segments to connect data points and shows changes in data over time. [http://www.icoachmath.com/math_dictionary/line_graph.html]

Line graph: A graph that uses points connected by lines to show how something changes in value (as time goes by, or as something else happens). [http://www.mathsisfun.com/definitions/line-graph.html]

line graph definition: a diagram of lines made by connected data points which represent successive changes in the value of a variable quantity or quantities. [http://dictionary.reference.com/browse/line+graph]

Was it just because they couldn’t spell “histogram” that elementary school teachers had to invent a new term confusingly close to an existing standard term?  I feel sorry for the kids subjected to this poor choice of nomenclature, as they will have to do more unlearning before taking high school or college tests, where they will be expected to know what a histogram and a line graph are, but not anything about “line plots”.