An artificial data set. 24 rats (12 female, 12 male) have been randomized to use one of three drugs (products for loosing weight). The weightloss for each rat is noted after one and two weeks.
A data frame with 4 variables.
a factor with two levels: "M" (male), "F" (female)
a factor with three levels: "D1", "D2", "D3" (three types)
a numeric: weightloss, week one.
a numeric: weightloss, week 2.
Morrison, D.F. (1976). Multivariate Statistical Methods. McGraw-Hill, USA.
Edwards, D. (1995). Introduction to Graphical Modelling, Springer-Verlag. New York.