kstones {GLMsData}

Treating kidney stones

Description

Treatment of kidney stones

Usage

data(kstones)

Format

A data frame with 8 observations on the following 4 variables.

Counts

the number of subjects in the given classification; a numeric vector

Size

whether the subject has kidney stones with mean diameter less than 2cm (coded as Small) or greater than or equal to 2cm (coded as Large); a factor with levels Large and Small

Method

the treatment method; a factor with levels A (open surgery) or B (percutaneous nephrolithotomy)

Outcome

the outcome of the stated treatment; a factor with levels Failure and Success

Details

The data give the success rates of two methods of treating kidney stones: open surgery methods, and percutaneous nephrolithotomy.

The given data are a subset of that reported by Charig et al. (1986), who also include two other methods of treatment, and also break up the open surgery methods into three sub-groups. The two methods here were chosen because they demonstrate Simpson's paradox.

Source

C. R. Charig, D. R. Webb, S. R. Payne, and J. A. E. Wickham (1986) Comparison of treatment of renal calculi by open surgery, percutaneous nephrolithotomy, and extracorpeal shockwave lithotripsy. British Medical Journal, 292, 29 March, 879–882.

Steven A. Julious and Mark A. Mullee (1994) Confounding and Simpson's paradox. British Medical Journal, 309(1480):1480–1481.

Examples

data(kstones)
summary(kstones)