cpplot {locfit}  R Documentation 
Compute a Cp plot.
Description
The cpplot
function loops through calls to the cp
function (and hence to link{locfit}
), using a different
smoothing parameter for each call.
The returned structure contains the Cp statistic for each fit, and can
be used to produce an AIC plot.
Usage
cpplot(..., alpha, sig2)
Arguments
... 

alpha 
Matrix of smoothing parameters. The 
sig2 
Residual variance. If not specified, the residual variance is computed using the fitted model with the fewest residual degrees of freedom. 
Value
An object with class "gcvplot"
, containing the smoothing
parameters and CP scores. The actual plot is produced using
plot.gcvplot
.
See Also
locfit
,
locfit.raw
,
gcv
,
aic
,
plot.gcvplot
Examples
data(ethanol)
plot(cpplot(NOx~E,data=ethanol,alpha=seq(0.2,1.0,by=0.05)))