crTest {DAMisc} R Documentation

## Test of linearity for Component + Residual Plots

### Description

This function estimates a linear model and a loess model on the component-plus-residual plot (i.e., a partial residual plot) for each quantitative variable in the model. The residual sums of squares for each are used to calculate an F-test for each quantitative variable.

### Usage

crTest(
model,
cat = 5,
var = NULL,
span.as = TRUE,
span = 0.75,
...
)


### Arguments

 model A model object of class lm adjust.method Adjustment method for multiple-testing procedure, using p.adjust from stats. cat Number of unique values below which numeric variables are considered categorical for the purposes of the smooth. var Character string indicating the term desired for testing. If left NULL, the default value, all numeric variables will be tested. span.as Logical indicating whether the span should be automatically selected through AICC or GCV span Span to be passed down to the loess function if span.as=FALSE. ... Other arguments to be passed down to the call to loess.

### Value

A matrix with the following columns for each variable:

 RSSp Residual sum-of-squares for the parametric (linear) model. RSSnp Residual sum-of-squares for the non-parametric (loess) model. DFnum Numerator degrees of freedom for the F-test: tr(S)-(k+1). DFdenom Denominator degrees of freedom for the F-test: n-tr(S) F F-statistic p p-value, potentially adjusted for multiple comparisons.

Dave Armstrong

### Examples


data(Prestige, package="carData")
mod <- lm(prestige ~ income + education + women, data=Prestige)
crTest(mod)



[Package DAMisc version 1.7.2 Index]