This is a three-factor experiment with each factor at three levels, for a total of 27 runs. Samples of worsted yarn were with different levels of the three factors were given a cyclic load until the sample failed. The goal is to understand how cycles to failure depends on the factors.
WoolThis data frame contains the following columns:
length of specimen (250, 300, 350 mm)
amplitude of loading cycle (8, 9, 10 min)
load (40, 45, 50g)
number of cycles until failure
Fox, J. and Weisberg, S. (2011) An R Companion to Applied Regression, Second Edition, Sage.
Weisberg, S. (2014) Applied Linear Regression, Fourth Edition, Wiley, Section 6.3.