pneumo: Pneumoconiosis in Coalminers Data

Description Usage Format Details Source References See Also Examples

Description

The pneumo data frame has 8 rows and 4 columns. Exposure time is explanatory, and there are 3 ordinal response variables.

Usage

1

Format

This data frame contains the following columns:

exposure.time

a numeric vector, in years

normal

a numeric vector, counts

mild

a numeric vector, counts

severe

a numeric vector, counts

Details

These were collected from coalface workers. In the original data set, the two most severe categories were combined.

Source

Ashford, J.R., 1959. An approach to the analysis of data for semi-quantal responses in biological assay. Biometrics, 15, 573–581.

References

McCullagh, P. and Nelder, J. A. (1989). Generalized Linear Models, 2nd ed. London: Chapman & Hall.

See Also

cumulative.

Examples

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# 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, propodds, data = pneumo)

Example output

Loading required package: stats4
Loading required package: splines

Call:
vglm(formula = cbind(normal, mild, severe) ~ let, family = propodds, 
    data = pneumo)


Coefficients:
(Intercept):1 (Intercept):2           let 
    -9.676093    -10.581725      2.596807 

Degrees of Freedom: 16 Total; 13 Residual
Residual deviance: 5.026826 
Log-likelihood: -25.09026 

VGAM documentation built on Jan. 16, 2021, 5:21 p.m.