SAS Macro Programs for Statistical Graphics: CONTOUR

CONTOUR macro ( get contour.sas)

Parameters

DATA=_LAST_

Name of the input data set

X=

Name of the X variable

Y=

Name of the Y variable

GROUP=

Group variable. If a GROUP= variable is specified, one ellipse is produced for each value of this variable in the data set. If no GROUP= variable is specified, a single ellipse is drawn for the entire sample. The GROUP= variable may be character or numeric.

PVALUE=.5

Confidence coefficient(s) ( 1 - alpha ) . This is the proportion of data from a bivariate normal distribution contained within the ellipse. Several values may be specified in a list (e.g., PVALUE=.5 .9), in which case one ellipse is generated for each value.

STD=STDERR

Error bar metric. STD=STDERR gives error bars equal to each mean +- one standard error ( s / sqrt n ) for both variables. STD=STD gives error bars whose length is one standard deviation for both variables.

POINTS=40

The number of points on each contour.

ALL=NO

Specifies whether the contour for the total sample should be drawn in addition to those for each group. If there is no GROUP= variable, ALL=YES just draws the ellipse twice.

OUT=CONTOUR

Name of the output Annotate data set used to draw the ellipses, error bars and group labels.

PLOT=YES

If YES, the macro plots the data together with the generated ellipses. Otherwise, only the output Annotate data set is generated.

I=NONE

SYMBOL statement interpolate option for drawing points. Use I=RL to include the regression line as well.

NAME=CONTOUR

The name assigned to the graph(s) in the graphic catalog.

COLORS=RED GREEN BLUE BLACK PURPLE YELLOW BROWN ORANGE

List of colors to use for each of the groups. If there are g groups, specify g colors if ALL=NO, and g + 1 colors if ALL=YES. COLORS(i) is used for group i.

SYMBOLS=+ SQUARE STAR - PLUS : $ =

List of symbols, separated by spaces, to use for plotting points in each of the groups. SYMBOLS(i) is used for group i.

Missing data

Usage Notes

When displaying output from the macro on a terminal, it may be necessary to specify CBACK=WHITE in a GOPTIONS statement.

Example

%include data(auto) ;
%contour(data=auto,
         x=price, y=weight, group=origin,
         pvalue=.5);