Arthritis {vcd} | R Documentation

## Arthritis Treatment Data

### Description

Data from Koch & Edwards (1988) from a double-blind clinical trial investigating a new treatment for rheumatoid arthritis.

### Usage

    data(Arthritis)

### Format

A data frame with 84 observations and 5 variables.

ID
  patient ID.
Treatment
  factor indicating treatment (Placebo, Treated).
Sex
  factor indicating sex (Female, Male).
Age
  age of patient.
Improved
  ordered factor indicating treatment outcome (None, Some, Marked).

### Source

Michael Friendly (2000), Visualizing Categorical Data: http://euclid.psych.yorku.ca/ftp/sas/vcd/catdata/arthrit.sas

### References

G. Koch & S. Edwards (1988), Clinical efficiency trials with categorical data. In K. E. Peace (ed.), Biopharmaceutical Statistics for Drug Development, 403–451. Marcel Dekker, New York.

M. Friendly (2000), Visualizing Categorical Data. SAS Institute, Cary, NC.

### Examples

    data(Arthritis)

    ## construct a table of interest using xtabs() or structable()
    ## via formula
    structable(Sex ~ Treatment + Improved, data = Arthritis)

    ## via default interface
    attach(Arthritis)
    structable(Treatment, Sex, Improved)
    detach(Arthritis)

    ## via xtabs and ftable
    ftable(xtabs(~Treatment + Improved + Sex, data = Arthritis))

[Package vcd version 0.9-6 Index]