BodyWeight               package:nlme               R Documentation

Rat weight over time for different diets

Description:

     The 'BodyWeight' data frame has 176 rows and 4 columns.

Format:

     This data frame contains the following columns:

     weight a numeric vector giving the body weight of the rat (grams).

     Time a numeric vector giving the time at which the measurement is
          made (days).

     Rat an ordered factor with levels '2' < '3' < '4' < '1' < '8' <
          '5' < '6' < '7' < '11' < '9' < '10' < '12' < '13' < '15' <
          '14' < '16' identifying the rat whose weight is measured.

     Diet a factor with levels '1' to '3' indicating the diet that the
          rat receives.


Details:

     Hand and Crowder (1996) describe data on the body weights of rats
     measured over 64 days.  These data also appear in Table 2.4 of
     Crowder and Hand (1990).  The body weights of the rats (in grams)
     are measured on day 1 and every seven days thereafter until day
     64, with an extra measurement on day 44. The experiment started
     several weeks before ``day 1.''  There are three groups of rats,
     each on a different diet.

Source:

     Pinheiro, J. C. and Bates, D. M. (2000), _Mixed-Effects Models in
     S and S-PLUS_, Springer, New York. (Appendix A.3)

     Crowder, M. and Hand, D. (1990), _Analysis of Repeated Measures_,
     Chapman and Hall, London.

     Hand, D. and Crowder, M. (1996), _Practical Longitudinal Data
     Analysis_, Chapman and Hall, London.

