R: Weight gain for different methionine sources

methionine {drc} | R Documentation

## 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)

[Package drc version 3.0-1 Index]