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#
Plots

Most plots may be produced by choosing **summary** from the analysis
menu. Some plots (like residual plots) are produced in the **regression**
module. Here is how the summary page looks like after the Height-Weight
data is entered.

The following graphs are produced in the **summary** module by choosing
the variable(s) and clicking on the name of the plot. (We will only list
those that are used in the course.) As illustrations we will give plots
of the variable Weight in the Height-Weight data.

Boxplots
Stem and Leaf Plots
Rweb:> stem(Weight)
The decimal point is 1 digit(s) to the right of the |
16 | 0
18 | 55
20 | 589
22 | 2550

Scatterplots - at least two variables have to be selected for a scatterplot
to be produced. The scatterplot of Height vs Weight is
Comparison Boxplots - Comparison boxplots are produced by adding an auxilliary
variable when the data is entered. For example, if we need a comparison
boxplot of *X* and *Y* in the following data set
x y
74 73
75 78
77 76
73 72
69 65
73 64
78
76
77
78

we need to stack the two columns into one column and add a variable indicating
whether the value is a *X* or a *Y*. Let's use "0" for *X*
and "1" for *Y*. The data entered will be as follows.
xy ind
74 0
75 0
77 0
73 0
69 0
73 0
78 0
76 0
77 0
78 0
73 1
78 1
76 1
72 1
65 1
64 1

The variables "xy" and "ind" will now show in the **summary** module.
Choose "xy" and split boxplot on "ind". Here is what the choices should
look like.
Here is what the comparison boxplot looks like.

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Statistics
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Entry

*2000-08-21*