The Dotplot is similar to the histogram but frequency is represented by the number of dots. A dot represents one observation or a group of observations if they are of the same or about the same value. The dots are plotted along the x-axis which are divided into intervals and dots are stacked vertically if there is more than one in the same interval. The Dotplot is useful for comparing and assessing distributions.
At the Excel Menu (For Excel 2007, go to Add-ins first)
Choose ProcessMA > Graphs > Dotplot
For data in single stacked column
In Variable, select the column containing the data (Numeric)
In Subgroup, select the column containing subgroup indicators (Optional)
For data in different columns
In Variables, select the columns containing the response data (Numeric, >= 2 variables)
Click OK
A company makes steel bolts using four different machines. You want to assess if the dimensions of the steel bolts made by different machines are the same. You want to use the Dotplot to compare the distributions.
Open data worksheet by choosing ProcessMA > Tools > Data
Choose ProcessMA > Graphs > Dotplot
In Variable, select B - Dimension
In Subgroup, select C - Machine
Click OK
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