The SGPLOT Procedure

PBSPLINE Statement

Creates a fitted penalized B-spline curve.

Syntax

PBSPLINE x= numeric-variable y= numeric-variable </ options>;

option(s) can be one or more options from the following categories:

PBSPLINE options:

	ALPHA= numeric-value
	CLI <= "text-string">
	CLIATTRS= style-element
	CLM <= "text-string">
	CLMATTRS= style-element
	CLMTRANSPARENCY= value
	CURVELABEL <= "text-string">
	CURVELABELLOC= OUTSIDE \| INSIDE
	CURVELABELPOS= MIN \| MAX \| START \| END
	DATALABEL <= variable>
	DEGREE= n
	FREQ= numeric-variable
	LINEATTRS= style-element <(options)> \| (options)
	MARKERATTRS= style-element <(options)> \| (options)
	MAXPOINTS= n
	NKNOTS= n
	NOLEGCLI
	NOLEGCLM
	NOLEGFIT
	NOMARKERS
	SMOOTH= numeric-value
	WEIGHT= numeric-variable

Plot options:

GROUP= variable

LEGENDLABEL= "text-string"

NAME= "text-string"

X2AXIS

Y2AXIS

Required Arguments

X= numeric-variable: specifies the variable for the x axis.
Y= numeric-variable: specifies the variable for the y axis.

Options

ALPHA= numeric-value

specifies the confidence level for the confidence limits. Specify a number between 0.00 (100% confidence) and 1.00 (0% confidence).

Note: This option has no effect if you do not specify either the CLI option or CLM option. [cautionend]

Default:

.05

CLI <= "text-string">

creates prediction limits for the individual predicted values. The optional text string overrides the default legend label for the prediction limits.

CLIATTRS = style-element

specifies the appearance of the individual value prediction limits by using an ODS style element.

Default:

The default appearance of the prediction limits is specified by the GraphPredictionLimits style element in the current style.

CLM <= "text-string">

creates confidence limits for the mean predicted values. The optional text string overrides the default legend label for the confidence limits.

CLMATTRS = style-element

specifies the appearance of the mean value confidence limits by using an ODS style element.

Default:

The default appearance of the confidence limits is specified by the GraphConfidence style element in the current style.

CLMTRANSPARENCY= numeric-value

specifies the degree of transparency for the confidence limits. Specify a value from 0.0 (completely opaque) to 1.0 (completely transparent).

Note: This option has no effect if you do not specify the CLM option. [cautionend]

Default:

0.0

CURVELABEL <="text-string">

adds a label for the spline curve. You can also specify the label text. If you do not specify a label, then the label from the Y variable is used.

CURVELABELLOC= OUTSIDE | INSIDE

specifies whether the curve label is placed inside the plot axes (INSIDE) or outside of the plot axes (OUTSIDE).

Default:

INSIDE

CURVELABELPOS= MIN | MAX | START | END

specifies the location of the curve label. Specify one of the following values:

MIN: places the curve label at the minimum value for the X axis.
MAX: places the curve label at the maximum value for the X axis.
START: places the curve label at the first point on the curve.
END: places the curve label at the last point on the curve.

Default:

END

DATALABEL <= variable>

displays a label for each scatter point. If you specify a variable, the values of that variable are used for the data labels. If you do not specify a variable, then the values of the Y variable are used for the data labels.

Interaction:

This option has no effect if you also specify the NOMARKERS option.

DEGREE= n

specifies the degree of the spline transformation.

Default:

FREQ= numeric-variable

specifies that each observation is repeated n times for computational purposes, where n is the value of the numeric variable. If n is not an integer, then it is truncated to an integer. If n is less than 1 or missing, then it is excluded from the analysis.

GROUP= variable

specifies a variable that is used to group the data. A separate plot is created for each unique value of the grouping variable. The plot elements for each group value are automatically distinguished by different visual attributes.

Interaction:

If you specify the GROUP= option in multiple fit plot statements, then the first GROUP= variable is used for all of the fit plots that specify GROUP=.

LEGENDLABEL= "text-string"

specifies a label that identifies the B-spline curve in the legend. By default, the label "Penalized B-Spline" is used with the SMOOTH= value if specified, or else the group value for each B-spline is used.

LINEATTRS= style-element <(options)> | (options)

specifies the appearance of the fitted curve. You can specify the appearance by using a style element or by using suboptions. If you specify a style element, you can additionally specify suboptions to override specific appearance attributes.

options can be one or more of the following:

COLOR= color

specifies the color of the line. For more information about specifying colors, see SAS/GRAPH Colors and Images in the SAS/GRAPH: Reference, Second Edition.

Default:

For ungrouped data, the default color is specified by the ContrastColor attribute of the GraphFit style element in the current style.

For grouped data, the default color is specified by the ContrastColor attribute of the GraphData1 ... GraphDatan style elements in the current style.

PATTERN= line-pattern

specifies the line pattern for the line. You can reference SAS patterns by number or by name. See Line Patterns for a list of line patterns.

Default:

For ungrouped data, the default line pattern is specified by the LineStyle attribute of the GraphFit style element in the current style.

For grouped data, the default line pattern is specified by the LineStyle attribute of the GraphData1 ... GraphDatan style elements in the current style.

THICKNESS= n <units>

specifies the thickness of the line. You can also specify the unit of measure. The default unit is pixels. See Units of Measurement for a list of the measurement units that are supported.

Default:

For ungrouped data, the default line thickness is specified by the LineThickness attribute of the GraphFit style element in the current style.

For grouped data, the default line thickness is specified by the LineThickness attribute of the GraphData1 ... GraphDatan style elements in the current style.

MARKERATTRS= style-element <(options)> | (options)

specifies the appearance of the markers in the plot. You can specify the appearance by using a style element or by using suboptions. If you specify a style element, you can additionally specify suboptions to override specific appearance attributes.

options can be one or more of the following:

COLOR= color

specifies the color of the markers. For more information about specifying colors, see SAS/GRAPH Colors and Images in the SAS/GRAPH: Reference, Second Edition.

Default:

For ungrouped data, the default color is specified by the ContrastColor attribute of the GraphDataDefault style element in the current style.

For grouped data, the default color is specified by the ContrastColor attribute of the GraphData1 ... GraphDatan style elements in the current style.

SIZE= n <units >

specifies the size of the markers. You can also specify the unit of measurement. The default unit is pixels. See Units of Measurement for a list of the measurement units that are supported.

Default:

The default marker size is specified by the MarkerSize attribute of the GraphDataDefault style element in the current style.

SYMBOL= symbol-name

specifies the symbol for the markers. See Marker Symbols for a list of valid marker symbols.

Default:

For ungrouped data, the default marker symbol is specified by the MarkerSymbol attribute of the GraphDataDefault style element in the current style.

For grouped data, the default marker symbol is specified by the MarkerSymbol attribute of the GraphData1 ... GraphDatan style elements in the current style.

MAXPOINTS= n

specifies the maximum number of predicted points for the spline curve and for any confidence limits.

Default:

201

NAME= "text-string"

specifies a name for the plot. You can use the name to refer to this plot in other statements.

NKNOTS= n

specifies the number of evenly spaced internal knots.

Default:	100
Range:	1 to 1000

NOLEGCLI

hides the legend entry for the individual value prediction limits.

NOLEGCLM

hides the legend entry for the mean value confidence limits.

NOLEGFIT

hides the legend entry for the fit line.

NOMARKERS

removes the scatter markers from the plot.

SMOOTH= numeric-value

specifies a smoothing parameter value. If you do not specify this option, a smoothing value is determined automatically.

WEIGHT= numeric-variable

specifies that each observation is weighted by a factor of w for computational purposes, where w is the value of the numeric variable. w can be any numeric value. If w is 0, negative or missing, then that observation is excluded from the analysis.

X2AXIS

assigns the X variable to the secondary (top) horizontal axis.

Y2AXIS

assigns the Y variable to the secondary (right) vertical axis.

Details

For the SMOOTH= option, the smoothing parameter value must be greater than the minimum value that is determined by the following equation:

[equation]

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	GROUP= variable
	LEGENDLABEL= "text-string"
	NAME= "text-string"
	X2AXIS
	Y2AXIS