salmonellaTA98 {flexmix} | R Documentation

## Salmonella reverse mutagenicity assay

### Description

Data on Ames Salmonella reverse mutagenicity assay.

### Usage

    data("salmonellaTA98")

### Format

This data frame contains the following columns:

x
  Dose levels of quinoline.
y
  Numbers of revertant colonies of TA98 Salmonella observed on each of three replicate plates tested at each of six dose levels of quinoline diameter.

### Details

This data set is taken from package dispmod provided by Luca Scrucca.

### Source

Margolin, B.J., Kaplan, N. and Zeiger, E. (1981) Statistical analysis of the Ames Salmonella/microsome test, Proc. Natl. Acad. Sci. USA, 76, 3779–3783.

### References

Breslow, N.E. (1984), Extra-Poisson variation in log-linear models, Applied Statistics, 33, 38–44.

Wang, P., Puterman, M.L., Cockburn, I.M., and Le, N.D. (1996) Mixed Poisson regression models with covariate dependent rates, Biometrics, 52, 381–400.

### Examples

    data("salmonellaTA98")
    salmonMix <- stepFlexmix(y ~ 1,
                             data = salmonellaTA98,
                             model = FLXMRglmfix(family = "poisson",
                               fixed = ~ x + log(x + 10)),
                             k = 2, nrep = 5)
    salmonMix.pr <- predict(salmonMix, newdata = salmonellaTA98)
    plot(y ~ x, data = salmonellaTA98,
         pch = as.character(clusters(salmonMix)),
         ylim = range(c(salmonellaTA98$y, unlist(salmonMix.pr))))
    for (i in 1:2) lines(salmonellaTA98$x, salmonMix.pr[[i]], lty = i)

[Package flexmix version 2.2-4 Index]