Weight gain for different methionine sources

Description

Data consist of average body weight gain of chickens being treated with one of the two methionine sources DLM and HMTBA.

Usage

data(methionine)

Format

A data frame with 9 observations on the following 3 variables:

product

a factor with levels control, DLM and MHA denoting the treatments

dose

a numeric vector of methionine dose

gain

a numeric vector of average body weight gain

Details

The dataset contains a common control measurement for the two treatments. More examples using this dataset are found under AR.2 and MM.2.

Source

Kratzer. D. D. and Littell, R. C. (2006) Appropriate Statistical Methods to Compare Dose Responses of Methionine Sources, Poultry Science, 85, 947–954.

Examples

## Fitting model with constraint on one parameter 
met.ar.m1 <- drm(gain~dose, product, data = methionine, 
fct = AR.3(), pmodels = list(~1, ~factor(product), ~factor(product)), 
upperl = c(Inf, Inf, 1700, Inf, Inf)) 

plot(met.ar.m1, xlim=c(0,0.3), ylim=c(1450, 1800))
abline(h=1700, lty=1)

summary(met.ar.m1)