display.delstats {gvlma} | R Documentation |
Creates a graph of the p-values associated with the deletion statistics
versus the deletion statistics with
unusual observations highlighted. This function is called by
plot.gvlmaDel
.
display.delstats(deletedStatvals, deletedpvals, nsd = 3, TukeyStyle = TRUE, statname = "G", pointlabels)
deletedStatvals |
The vector of deletion statistics, with i-th entry defined as the percent relative change in the global test statistic when the i-th observation is removed from the analysis. |
deletedpvals |
The vector of p-values associated with the global test statistics, with i-th entry being the p-value for the global test statistic with observation i removed. |
nsd |
Parameter that governs which observations are deemed
unusual. When TukeyStyle = TRUE , “control limits” are
drawn nsd
times the interquartile range beyond the quartiles for both the
deletedStatvals and deletedpvals . When TukeyStyle
= FALSE , “control limits” are drawn at nsd standard deviations away
from the sample means. Observations beyond these “control limits” are
marked and labeled using the text in pointlabels, if provided (else by
observation number). |
TukeyStyle |
Controls how unusual observations are determined.
If TukeyStyle = TRUE (default), then unusual observations are farther than
nsd times the
interquartile range from the quartiles (in either of the
deletedStatvals and deletedpvals directions). If TukeyStyle = FALSE , then
unusual observations are farther than nsd times the sample standard
deviation from the sample mean. |
statname |
A string used to label the deletedStatvals axis of the
plot. If missing, this label is determined from the variable name
passed as the deletedStatvals argument, if possible; otherwise
defaults to "Deleted statistics." |
pointlabels |
Character vector of same length as deletedStatvals
and deletedpvals used for labelling unusual observations. |
Generally display.delstats
is not called directly, but rather
by the function plot.gvlmaDel
.
Plots the deletedpvals
versus the deletedStatvals
and adds
“control
limits” determined by the parameters nsd
and TukeyStyle
.
Points outside
the “control limits” (in either the deletedStatval
or
deletedpval
) are
labeled as unusual.
A dataframe consisting of the unusual observations with variables
deletedStatval
and deletedpval
.
Slate, EH SlateEH@musc.edu and Pena, EA pena@stat.sc.edu.
Pena, EA and Slate, EH (2006). “Global validation of linear model assumptions,” J. Amer. Statist. Assoc., 101(473):341-354.
data(CarMileageData) CarMileageAssess <- gvlma(NumGallons ~ MilesLastFill + NumDaysBetw, data = CarMileageData) CarMileageDel <- deletion.gvlma(CarMileageAssess) plot(CarMileageDel) display.delstats(CarMileageDel$DeltaGlobalStat, CarMileageDel$GStatpvalue) display.delstats(CarMileageDel$DeltaStat1, CarMileageDel$Stat1pvalue)