cabbages data set has 60 observations and 4 variables
This data frame contains the following columns:
Factor giving the cultivar of the cabbage, two levels:
Factor specifying one of three planting dates:
Weight of the cabbage head, presumably in kg.
Ascorbic acid content, in undefined units.
Rawlings, J. O. (1988) Applied Regression Analysis: A Research Tool. Wadsworth and Brooks/Cole. Example 8.4, page 219. (Rawlings cites the original source as the files of the late Dr Gertrude M Cox.)
Venables, W. N. and Ripley, B. D. (1999) Modern Applied Statistics with S-PLUS. Third Edition. Springer.