haldport {RXshrink} | R Documentation |
Heat evolved during setting of 13 cement mixtures of four basic ingredients. Each ingredient percentage appears to be rounded down to a full integer. The sum of the four mixture percentages varies from a maximum of 99% to a minimum of 95%. If all four regressor X-variables always summed to 100%, the centered X-matrix would then be of rank only 3. Thus, the regression of heat on four X-percentages is ill-conditioned, with an approximate rank deficiency of MCAL = 1.
data(haldport)
A data frame with 13 observations on the following 5 variables.
p3ca
p3cs
p4caf
p2cs
heat
The (RXshrink) haldport data are identical to the (MASS) cement data except for variable names.
Woods H, Steinour HH, Starke HR. "Effect of composition of Portland cement on heat evolved during hardening. Industrial Engineering and Chemistry 1932; 24: 1207-1214.
Hald A. Statistical Theory with Engineering Applications. 1952 (page 647.) New York; Wiley.