drc (version 4.0-0)

deguelin: Deguelin applied to chrysanthemum aphis

Description

Quantal assay data from an experiment where the insectide deguelin was applied to Macrosiphoniella sanborni.

Usage

data(deguelin)

Format

A data frame with 6 observations on the following 4 variables.

dose

a numeric vector of doses applied

log10dose

a numeric vector of logarithm-transformed doses

r

a numeric vector contained number of dead insects

n

a numeric vector contained the total number of insects

Details

The log-logistic model provides an inadequate fit.

The dataset is used in Nottingham and Birch (2000) to illustrate a semiparametric approach to dose-response modelling.

References

Notttingham, Q. J. and Birch, J. B. (2000) A semiparametric approach to analysing dose-response data, Statist. Med. 19, 389--404.

Examples

## Log-logistic fit
deguelin.m1 <- drm(r/n ~ dose, weights=n, data = deguelin, fct = LL.2(), type = "binomial")
modelFit(deguelin.m1)
summary(deguelin.m1)

## Loess fit
deguelin.m2 <- loess(r/n ~ dose, data = deguelin, degree = 1)

## Plot of data with fits superimposed
plot(deguelin.m1, ylim = c(0.2, 1))
lines(1:60, predict(deguelin.m2, newdata = data.frame(dose = 1:60)), col = 2, lty = 2)

pred1 <- predict(deguelin.m1, newdata = data.frame(dose = 1:60), se = FALSE)
pred2 <- predict(deguelin.m2, newdata = data.frame(dose = 1:60))
lines(1:60, 0.05 * pred1 + 0.95 * pred2, col = 3, lty = 3)