Hald {BAS} | R Documentation

## Hald Data

### Description

The Hald data have been used in many books and papers to illustrate variable selection. The data relate to an engineering application that was concerned with the effect of the composition of cement on heat evolved during hardening. The response variable Y is the heat evolved in a cement mix. The four explanatory variables are ingredients of the mix, X1: tricalcium aluminate, X2: tricalcium silicate, X3: tetracalcium alumino ferrite, X4: dicalcium silicate. An important feature of these data is that the variables X1 and X3 are highly correlated, as well as the variables X2 and X4. Thus we should expect any subset of (X1,X2,X3,X4) that includes one variable from highly correlated pair to do as any subset that also includes the other member.

### Format

`hald` is a dataframe with 13 observations and 5 variables (columns),

Y: Heat evolved per gram of cement (in calories) X1: Amount of tricalcium aluminate X2: Amount of tricalcium silicate X3: Amount of tetracalcium alumino ferrite X4: Amount of dicalcium silicate

### Source

Wood, H., Steinour, H.H., and Starke, H.R. (1932). "Effect of Composition of Portland cement on Heat Evolved During Hardening", Industrial and Engineering Chemistry, 24, 1207-1214.

[Package BAS version 1.5.3 Index]