Cement hardening data from Woods et al (1932).
CementCement is a data frame with 5 variables. x1-x4 are four predictor
variables expressed as a percentage of weight.
calories of heat evolved per gram of cement after 180 days of hardening
calcium aluminate
tricalcium silicate
tetracalcium alumino ferrite
dicalcium silicate.
Burnham, K. P. and Anderson, D. R (2002) Model selection and multimodel inference: a practical information-theoretic approach. 2nd ed. New York, Springer-Verlag.