xdistResdiff: Residual Differences for Near Replicates: Tabulate and Test

In plgraphics: User Oriented Plotting Functions

Residual Differences for Near Replicates: Tabulate and Test

Description

A test for the completeness of a linear regression model can be performed based on comparing the differences of residuals for pairs of observations that are close to each other to the estimated standard deviation of the model.

Usage

xdistResdiff(object, perc = c(3, 10, 80), trim = 0.1,
  nmax = 100, out = "aggregate")
xdistResscale(x, perc = c(3, 10, 90), trim = 1/6)

Arguments

object	an object containing the result of fitting a linear model by regr
x	an object produced by xdistResdiff
perc	Percentage points to define distance classes
trim	Trimming proportion for calculating means of absolute residual differences
nmax	maximal number of observations to form pairs

out	determines the value of xdistResdiff: if =="aggregate" (the default), the value will be produced by calling xdistResscale, otherwise, all x distances and respective residual differences will be returned.

Details

See package vignette.

Value

For xdistResdiff with out="aggregate" and xdistResscale, a matrix is returned with a row for each class of x distances and the columns

xdist	mean x distance
rdiff.mean	absolute differences of residuals for pairs of observations in the distance class, averaged over the class
rdiff.simmean	mean of (trimmed) means for simulated data
rdiff.se	standard error of (trimmed) means as obtained from simulation

The matrix carries along the following attributes:

perc	given argument perc
xd.classlim	the actual class limits corresponding to perc
trim	given argument trim
rdiff.grandmean	overall mean of absolute residual differences
p-values	p values for the classes as obtained from simulation, and p-value for the sum of squares statistic
class	The value has S3 class xdistResscale and matrix

.

If xdistResdiff with out different from "aggregate", then a data.frame is returned containing a row for each pair of observations and the columns

id1, id2	the labels of the two observations
xdist	the x distance between the two observations
resdiff	the difference of residuals for the two observations

The value has S3 class xdistResdiff and data.frame.

Author(s)

Werner A. Stahel, ETH Zurich

References

See package vignette.

See Also

plot.xdistResscale

Examples

data(d.blast)
rr <- lm(tremor~distance+charge, data=d.blast)
## an inadequate model!
xdrs <- xdistResdiff(rr)
xdrd <- xdistResdiff(rr, out="all")
showd(xdrd)
xdrs <- xdistResscale(xdrd)
## same as first call of  xdiffResdiff
plot(xdrs)

plgraphics documentation built on Oct. 19, 2023, 3 p.m.