Statistics and Probability Dictionary
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Dotplot
A dotplot is a type of graphic display used to
compare frequency counts within categories or groups.
As you might guess, a dotplot is made up of dots plotted on a graph.
Here is how to interpret a dotplot.
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Each dot can represent a single observation from a set of data, or
a specified number of observations from a set of data.
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The dots are stacked in a
column over a category, so that the height of the column
represents the relative or absolute frequency of observations
in the category.
Here is an example to show what a dotplot looks like and how to
interpret it. Suppose 30 first graders are asked to pick their
favorite color. Their choices can be summarized in a dotplot,
as shown below.
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| Red |
Orange |
Yellow |
Green |
Blue |
Indigo |
Violet |
Each dot represents one student, and the number of dots in a column represents
the number of first graders who selected the color associated with
that column. For example, Red was the
most popular color (selected by 9 students), followed by Blue
(selected by 7 students). Selected by only 1 student, Indigo was the
least popular color.