choplump (version 1.0-0.3)

choplump-package: Choplump test package

Description

This package has basically one important function, choplump for performing the choplump test, which is for comparing two groups with some positive response and many zero responses. These tests can often be more powerful than simpler permutation tests. Exact and approximation methods are available for calculating p-values.

Details

ll{ Package: choplump Type: Package Version: 1.0-0.1 Date: 2010-07-30 License: GPL } See example below. There is also two vignettes. The vignette computation (see vignette("choplumpComputation")) gives computational details, and the vignette validation (see vignette("choplumpValidation")) details the way we have validated the function.

References

Follmann, DA, Fay, MP, and Proschan, MA. (2009) ''Chop-lump tests for Vaccine trials'' Biometrics 65: 885-893. (see /doc/choplump.pdf)

Examples

set.seed(13921)
Ntotal<-200
Mtotal<-54
Z<-rep(0,Ntotal)
Z[sample(1:Ntotal,Ntotal/2,replace=FALSE)]<-1
test<-data.frame(W=c(rep(0,Ntotal-Mtotal),abs(rnorm(Mtotal))),Z=Z)
## defaults to asymptotic approximation if the number 
## of calculations of the test statistic 
## is >methodRuleParms=10^4
choplump(W~Z,data=test,use.ranks=TRUE,exact=FALSE)