leprosy: Count of leprosy bacilli pre- and post-treatment from a...
In ALA: Data sets and examples for the book "Applied Longitudinal Analysis"

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The dataset consists of count data from a placebo-controlled clinical trial of 30 patients with leprosy at the Eversley Childs Sanitorium in the Philippines.

1	data(leprosy)

A data frame with 60 observations on the following 4 variables.

id: a factor with 30 levels
drug: a factor with levels A, B, and C indicating drug treatment (C: placebo)
period: a factor with levels pre and post
nBacilli: a numeric vector; bacilli count

Participants in the study were randomized to either of two antibiotics (denoted treatment drug A and B) or to a placebo (denoted treatment drug C). Prior to receiving treatment, baseline data on the number of leprosy bacilli at six sites of the body where the bacilli tend to congregate were recorded for each patient. After several months of treatment, the number of leprosy bacilli at six sites of the body were recorded a second time. The outcome variable is the total count of the number of leprosy bacilli at the six sites. In this study, the question of main scientific interest is whether treatment with antibiotics (drugs A and B) reduces the abundance of leprosy bacilli at the six sites of the body when compared to placebo (drug C).

Original variable names have been adapted to R conventions. Data were reshaped from wide to long format and the response named nBacilli.

http://biosun1.harvard.edu/~fitzmaur/ala

Snedecor GW, Cochran WG (1967) Statistical Methods, (6th edn). Ames, Iowa: Iowa State University Press