The
catalyst data frame is a design object. Its eight rows
represent all possible combinations of two
temperatures, two concentrations, and two catalysts. The fourth
column represents the response variable
Yield .
This data frame contains the following columns:
160 or
180 degrees.
20 or
40 .
A or
B .
Box, G. E., Hunter, W. G., and Hunter, S. (1978) Statistics for Experimenters.
J. Wiley and Sons, NY, p. 308.
John M. Chambers and Trevor J. Hastie, (eds.) Statistical Models in S,
Wadsworth and Brooks, Pacific Grove, CA 1992, pp. 147, 150--52.
aovcat<- aov(Yield ~ ., catalyst)
# the "." stands for all the variables in the data frame
# except the one to the left of the "~"