pneumo {VGAM} | R Documentation |
The pneumo
data frame has 8 rows and 4 columns.
Exposure time is explanatory, and there are 3 ordinal response variables.
data(pneumo)
This data frame contains the following columns:
These were collected from coalface workers. In the original data set, the two most severe categories were combined.
Ashford, J.R., 1959. An approach to the analysis of data for semi-quantal responses in biological assay. Biometrics, 15, 573–581.
McCullagh, P. and Nelder, J. A. (1989) Generalized Linear Models, 2nd ed. London: Chapman & Hall.
data(pneumo) # Fit the proportional odds model, p.179, in McCullagh and Nelder (1989) pneumo = transform(pneumo, let=log(exposure.time)) vglm(cbind(normal,mild,severe) ~ let, cumulative(parallel=TRUE, reverse=TRUE), pneumo)