R: Carcinogenic Effects of a Fungicide

Fungicide {vcdExtra} | R Documentation

## Carcinogenic Effects of a Fungicide

### Description

Data from Gart (1971) on the carcinogenic effects of a certain fungicide in two strains of mice. Of interest is how the association between `group` (Control, Treated) and `outcome` (Tumor, No Tumor) varies with `sex` and `strain` of the mice.

Breslow (1976) used this data to illustrate the application of linear models to log odds ratios.

### Usage

    data(Fungicide)

### Format

The data comprise a set of four 2 x 2 tables classifying 403 mice, either Control or Treated and whether or not a tumor was later observed. The four groups represent the combinations of sex and strain of mice. The format is: num [1:2, 1:2, 1:2, 1:2] 5 4 74 12 3 2 84 14 10 4 ... - attr(*, "dimnames")=List of 4 ..$ group : chr [1:2] "Control" "Treated" ..$ outcome: chr [1:2] "Tumor" "NoTumor" ..$ sex : chr [1:2] "M" "F" ..$ strain : chr [1:2] "1" "2"

### Details

All tables have some small cells, so a continuity correction is recommended.

### Source

Gart, J. J. (1971). The comparison of proportions: a review of significance tests, confidence intervals and adjustments for stratification. International Statistical Review, 39, 148-169.

### References

Brewlow, N. (1976), Regression analysis of the log odds ratio: A method for retrospective studies, Biometrics, 32(3), 409-416.

### Examples

    data(Fungicide)
    # loddsratio was moved to vcd; requires vcd_1.3-3+
    ## Not run:
    if (require(vcd)) {
    fung.lor <- loddsratio(Fungicide, correct=TRUE)
    fung.lor
    confint(fung.lor)
    }

    ## End(Not run)

    # visualize odds ratios in fourfold plots
    cotabplot(Fungicide, panel=cotab_fourfold)
    #  -- fourfold() requires vcd >= 1.2-10
    fourfold(Fungicide, p_adjust_method="none")

[Package vcdExtra version 0.7-1 Index]