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Example 52.6 Bivariate KDE Graphics

This example illustrates the available bivariate graphics in PROC KDE. The `octane`

data set comes from Rodriguez and Taniguchi (1980), where it is used for predicting customer octane satisfaction by using trained-rater observations. The variables in this
data set are `Rater`

and `Customer`

. Either variable might have missing values. See the file *kdex3.sas* in the SAS Sample Library. The following statements create the `octane`

data set:

data octane;
input Rater Customer;
label Rater = 'Rater'
Customer = 'Customer';
datalines;
94.5 92.0
94.0 88.0
94.0 90.0
93.0 93.0
... more lines ...
88.0 84.0
.H 90.0
;

The following statements request all the available bivariate plots in PROC KDE:

ods graphics on;
proc kde data=octane;
bivar Rater Customer / plots=all;
run;
ods graphics off;

Output 52.6.1 shows a scatter plot of the data, Output 52.6.2 shows a bivariate histogram of the data, Output 52.6.3 shows a contour plot of bivariate density estimate, Output 52.6.4 shows a contour plot of bivariate density estimate overlaid with a scatter plot of data, Output 52.6.5 shows a surface plot of bivariate kernel density estimate, and Output 52.6.6 shows a bivariate histogram overlaid with a bivariate kernel density estimate. These graphical displays are requested by
specifying the PLOTS= option in the BIVAR statement with ODS Graphics enabled. For general information about ODS Graphics, see Chapter 21: Statistical Graphics Using ODS. For specific information about the graphics available in the KDE procedure, see the section ODS Graphics.

Output 52.6.1: Scatter Plot

Output 52.6.2: Bivariate Histogram

Output 52.6.3: Contour Plot

Output 52.6.4: Contour Plot with Overlaid Scatter Plot

Output 52.6.5: Surface Plot

Output 52.6.6: Bivariate Histogram with Overlaid Surface Plot