MultNonParam (version 1.3.9)

probest: Stratified Multivariate Kawaguchi Koch Wang Estimators

Description

Function that return the estimators and their variance-covariance matrix calculated with the Kawaguchi - Koch - Wang method.

Usage

probest(ds, resp, grp, str = NULL, covs = NULL, delta = NA, correct = FALSE)

Value

A list with components b, the vector of adjusted estimates from the method, and Vb, the corresponding estimated covariance matrix.

Arguments

ds

The data frame to be used.

resp

The vector of the response manifest variable. There can be more than one variable. It has to be the name of the variable as a character string.

grp

The vector of the variable that divides the population into groups. It has to be the name of the variable as a character string.

str

The vector of the variable used for the strata. It has to be the name of the variable as a character string.

covs

The covariates to be used in the model. It has to be the name of the variable as a character string.

delta

Offeset for covariates.

correct

Should the variance estimator be corrected as in Chen and Kolassa?

Details

The function calls a Fortran code to calculate the estimators b and their variance-covariance matrix Vb

References

A. Kawaguchi, G. G. Koch and X. Wang (2012), "Stratified Multivariate Mann-Whitney Estimators for the Comparison of Two Treatments with Randomization Based Covariance Adjustment", Statistics in Biopharmaceutical Research 3 (2) 217-231.

J. E. Kolassa and Y. Seifu (2013), Nonparametric Multivariate Inference on Shift Parameters, Academic Radiology 20 (7), 883-888.

Examples

# Breast cancer data from the MultNonParam package.
data(sotiriou)
attach(sotiriou)
#First simple plot of the data
plot(AGE,TUMOR_SIZE,pch=(recur+1),main="Age and Tumor Size",
  sub="Breast Cancer Recurrence Data",xlab="Age (years)",
  ylab="Tumor Size",col=c("blue","darkolivegreen"))
legend(31,8,legend=c("Not Recurrent","Recurrent"),
  pch=1:2,col=c("blue","darkolivegreen"))
#AGE and TUMOR_SIZE are the response variables, recur is used for the groups,
#TAMOXIFEN_TREATMENT for the stratum and ELSTON.ELLIS_GRADE is a covariate.
po<-probest(sotiriou,c("AGE","TUMOR_SIZE"),"recur",
  "TAMOXIFEN_TREATMENT","ELSTON.ELLIS_GRADE")