Data from 99 ash samples originating from different biomass, measured on 9 variables; 8 log-transformed variables are added.
data(ash)A data frame with 99 observations on the following 17 variables.
SOTa numeric vector
P2O5a numeric vector
SiO2a numeric vector
Fe2O3a numeric vector
Al2O3a numeric vector
CaOa numeric vector
MgOa numeric vector
Na2Oa numeric vector
K2Oa numeric vector
log(P2O5)a numeric vector
log(SiO2)a numeric vector
log(Fe2O3)a numeric vector
log(Al2O3)a numeric vector
log(CaO)a numeric vector
log(MgO)a numeric vector
log(Na2O)a numeric vector
log(K2O)a numeric vector
The dependent variable Softening Temperature (SOT) of ash should be modeled by the elemental composition of the ash data. Data from 99 ash samples - originating from different biomass - comprise the experimental SOT (630-1410 centigrades), and the experimentally determined eight mass concentrations the listed elements. Since the distribution of the elements is skweed, the log-transformed variables have been added.
K. Varmuza and P. Filzmoser: Introduction to Multivariate Statistical Analysis in Chemometrics. CRC Press, Boca Raton, FL, 2009.