Weight versus age of chicks on different diets
a numeric vector giving the body weight of the chick (gm).
a numeric vector giving the number of days since birth when the measurement was made.
an ordered factor with levels 18 < ... < 48 giving a unique identifier for the chick. The ordering of the levels groups chicks on the same diet together and orders them according to their final weight (lightest to heaviest) within diet.
a factor with levels 1, ..., 4 indicating which experimental diet the chick received.
Crowder, M. and Hand, D. (1990). Analysis of Repeated Measures. London: Chapman and Hall. (example 5.3)
Hand, D. and Crowder, M. (1996), Practical Longitudinal Data Analysis. London: Chapman and Hall. (table A.2)
Pinheiro, J. C. and Bates, D. M. (2000) Mixed-effects Models in S and S-PLUS. New York: Springer.
t = octave.dataset.ChickWeight octave.examples.coplot (t, "Time", "weight", "Chick");