scedast {nnDiag} | R Documentation |
Assesses the relationship between standard deviations of residuals with respect to response variable predictions for a test of scedasticity.
scedast(object)
object |
object of class "nnDgrps" |
An object of class
"nnDsced"
, which is a list
containing the following components:
mean.prediction |
a vector of means of the groups of predictions |
stdev.residuals |
a vector of the standard deviations of the residual groups |
Brian Walters walte137@msu.edu
McRoberts, R.E. (2009) Diagnostic tools for nearest neighbors techniques when used with satellite imagery, Remote Sensing of Environment. 113, 489–499.
data(LuceVolume)
data(LuceVolume_indx)
##First use grouper to make the "nnDgrps"
object
grps <- grouper(LuceVolume$ref.volume, LuceVolume$pred.vol_k18, LuceVolume_indx)
x <- scedast(object = grps)
## Not run:
plot(x)
plot(x, ylab = "Standard Deviation of Volume Residuals (ft^3/acre)",
xlab = "Mean Volume Predictions(ft^3/acre)", ylim = c(500,2500), xlim =
c(500,2500), pch = 20)
## End(Not run)