Milk {nlme} | R Documentation

## Protein content of cows' milk

### Description

The `Milk` data frame has 1337 rows and 4 columns.

### Format

This data frame contains the following columns:

protein
  a numeric vector giving the protein content of the milk.
Time
  a numeric vector giving the time since calving (weeks).
Cow
  an ordered factor giving a unique identifier for each cow.
Diet
  a factor with levels `barley`, `barley+lupins`, and `lupins` identifying the diet for each cow.

### Details

Diggle, Liang, and Zeger (1994) describe data on the protein content of cows' milk in the weeks following calving. The cattle are grouped according to whether they are fed a diet with barley alone, with barley and lupins, or with lupins alone.

### Source

Diggle, Peter J., Liang, Kung-Yee and Zeger, Scott L. (1994), Analysis of longitudinal data, Oxford University Press, Oxford.

### Examples

    data(Milk)

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