plot.lmridge {lmridge}

VIF and Ridge Trace Plot

Description

Plot of VIF values (VIF trace) and ridge coefficients (ridge trace) for scalar or vector values of biasing parameter K.

Usage

## S3 method for class 'lmridge'
plot(x, type = c("ridge", "vif"), abline = TRUE, ...)

Arguments

x

An object of class "lmridge".

type

Either VIF trace or ridge trace.

abline

Horizontal and vertical line to show minimum value of MSE and GCV value at certain value of biasing parameter K on ridge and VIF trace respectively.

...

Not presently used in this implementation.

Details

Graphical way of selecting optimal value of biasing parameter K. The biasing parameter is selected when coefficients becomes stable in case of ridge trace. In cae of VIF trace K (ridge biasing parameter) can be selected for which VIF of each regressor near to one or value of K at which GCV is minimum. If no argument is used then all traces of ridge coefficients will be displayed. A vertical and horizontal line will also be displayed on ridge trace graph to indicate minimum ridge MSE (among the all computed ridge MSE based on provided vector of K) along with the value of respective biasing parameter K. For VIF trace, vetical line shows minmum GCV value at certain value of biasing parameter K.

Value

Nothing

Author(s)

Muhammad Imdad Ullah, Muhammad Aslam

References

Hoerl, A. E., Kennard, R. W., and Baldwin, K. F. (1975). Ridge Regression: Some Simulation. Communication in Statistics, 4, 105-123. doi:10.1080/03610927508827232.

Hoerl, A. E. and Kennard, R. W., (1970). Ridge Regression: Biased Estimation of Nonorthogonal Problems. Technometrics, 12, 55-67. doi:10.1080/00401706.1970.10488634.

Imdad, M. U. Addressing Linear Regression Models with Correlated Regressors: Some Package Development in R (Doctoral Thesis, Department of Statistics, Bahauddin Zakariya University, Multan, Pakistan), 2017.

See Also

The ridge model fitting lmridge, ridge CV and GCV plots cv.plot, variance bias trade-off plot bias.plot, m-scale and isrm plots isrm.plot, ridge AIC and BIC plots info.plot, miscellaneous ridge plots rplots.plot

Examples

mod <- lmridge(y~., as.data.frame(Hald), K = seq(0, 0.15, 0.002))
## Ridge trace
plot(mod)
plot(mod, type = "ridge")

## VIF trace
plot(mod, type = "vif")
## Ridge trace without abline
plot(mod, type = "ridge", abline = FALSE)