Dotplots. Mary Parker, January 21, 2013
Dotplots
When making a graph by hand of a small set of data on a quantitative variable, the easiest way is to simply
draw a number line and put dots above the number line in the appropriate places.
Whether you “stack up” the data values that are almost equal or not is a matter of choice. In the second
example below, see how the values 12.7 and 12.9 are “stacked up” because they are so close together in terms
of the scale of the graph.
Data
Test A
55
65
73
77
79
79
80
81
89
95
scores
43.2
18.1
12.7
12.9
37.9
21.8
24.7
24.9
13.7
26.8
17.2
20.2
Dotplot
Dotplot of Test A
54
60
66
72
78
84
90
Test A
Dotplot of Score
15
20
25
30
Score
35
40
96