specifies the degree of transparency for the density
curve.
Required Argument
response-variable
specifies the variable
for the x axis. The variable must be numeric.
Optional Arguments
FREQ= numeric-variable
specifies how many times observations are repeated
for computational purposes.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.
LEGENDLABEL= “text-string”
specifies a label that identifies the density plot
in the legend.By default, the label
identifies the type of density curve. If you specify TYPE=NORMAL,
then the default label is “Normal.” If you specify TYPE=KERNEL,
then the default label is “Kernel.”
Note:User-specified parameters from the TYPE= option are included
in the label by default.
LINEATTRS= style-element <(options)>
| (options)
specifies the appearance of the density line.You can specify the
appearance by using a style element or by using suboptions. If you
specify a style element, you can also specify suboptions to override
specific appearance attributes.
options can
be one or more of the following:
COLOR= color
specifies the color
of the line. You
can specify colors using the same color schemes that are supported
by SAS/GRAPH software. For more information, see Color-Naming Schemes in SAS/GRAPH: Reference.
Default:The default color is specified by the ContrastColor
attribute of the GraphFit style element in the current style.
PATTERN= line-pattern
specifies the line
pattern for the line. You can reference SAS patterns by number or by name. For a list of line patterns,
see Line Patterns.
Default:The default line pattern is specified by the LineStyle
attribute of the GraphFit style element 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. For
a list of measurement units that are supported, see Units of Measurement.
Default:The default line thickness is specified by the LineThickness
attribute of the GraphFit style element in the current style.
NAME= “text-string”
specifies a name for the plot.You can use the name
to refer to this plot in other statements.
Note:The name is case-sensitive. When you refer to the specified
name in other statements, you must use the same exact capitalization.
SCALE= COUNT | DENSITY | PERCENT | PROPORTION
specifies the scaling that is used for the response
axis.Specify one of the
following values:
COUNT
the axis displays the
frequency count.
DENSITY
the axis displays the
density estimate values.
PERCENT
the axis displays values
as a percentage of the total.
PROPORTION
the axis displays values
in proportion to the total.
Default:PERCENT
TRANSPARENCY= numeric-value
specifies the degree of transparency for the density
curve.Specify a value from
0.0 (completely opaque) to 1.0 (completely transparent).
Default:0.0
TYPE = NORMAL < (normal-opts)>|
KERNEL < (kernel-opts)>
specifies the type of distribution curve that is
used for the density plot.Specify one of the
following keywords:
NORMAL < (normal-opts)>
specifies a normal
density estimate, with a mean and a standard deviation.
normal-opts can
be one or more of the following values:
MU=numeric-value
specifies the mean
value that is used in the density function equation. By default, the
mean value is calculated from the data.
SIGMA=numeric-value
specifies the standard
deviation value that is used in the density function equation. The
value that you specify for the SIGMA= suboption must be a positive
number. By default, the standard deviation value is calculated from
the data.
KERNEL < (kernel-opts)>
specifies a nonparametric
kernel density estimate.
kernel-opts can
be:
C= numeric-value
specifies the standardized
bandwidth for a number that is greater than 0 and less than or equal
to 100.
The value that you
specify for the C= suboption affects the value of λ as shown
in the following equation:
In this equation c is
the standardized bandwidth, Q is
the interquartile range, and n is
the sample size.
WEIGHT= NORMAL | QUADRATIC | TRIANGULAR
specifies the weight
function. You can specify either normal, quadratic, or triangular
weight function.
Default:NORMAL
Default:NORMAL
Details
Normal Density Function
When the type of the density
curve is NORMAL, the fitted density function equation is as follows.
In the equation, μ
is the mean, and σ is the standard deviation. You can specify
μ by using the MU= suboption and σ by using the SIGMA=
suboption.
Kernel Density Function
When the TYPE of the density
curve is KERNEL, the general form of the kernel density estimator
is as follows.
In the equation, is the weight function, λ is the bandwidth, n is
the sample size, and is the ith
observation. You can use the C= suboption to specify the bandwidth
and the WEIGHT= suboption to specify the weight function .
Kernel Density Weight Functions
The formulas for the weight functions are as follows.