Alfalfa                 package:nlme                 R Documentation

Split-Plot Experiment on Varieties of Alfalfa

Description:

     The 'Alfalfa' data frame has 72 rows and 4 columns.

Format:

     This data frame contains the following columns:

     Variety a factor with levels 'Cossack', 'Ladak', and  'Ranger' 

     Date a factor with levels 'None'  'S1'  'S20'  'O7' 

     Block a factor with levels '1'  '2'  '3'  '4'  '5'  '6' 

     Yield a numeric vector

Details:

     These data are described in Snedecor and Cochran (1980) as an
     example of a split-plot design. The treatment structure used in
     the experiment was a 3times4 full factorial, with three varieties
     of alfalfa and four dates of third cutting in 1943. The
     experimental units were arranged into six blocks, each subdivided
     into four plots. The varieties of alfalfa (_Cossac_, _Ladak_, and
     _Ranger_) were assigned randomly to the blocks and the dates of
     third cutting (_None_, _S1_-September 1, _S20_-September 20, and
     _O7_-October 7) were randomly assigned to the plots.  All four
     dates were used on each block.

Source:

     Pinheiro, J. C. and Bates, D. M. (2000), _Mixed-Effects Models in
     S and S-PLUS_, Springer, New York.  (Appendix A.1)

     Snedecor, G. W. and Cochran, W. G. (1980), _Statistical Methods
     (7th ed)_, Iowa State University Press, Ames, IA

Examples:

     data(Alfalfa)

