| defoam {EngrExpt} | R Documentation |
The height of a solution containing a “defoamer” in a 50-ml graduated cylinder after being heated to a particular temperature.
A data frame with 27 observations on the following 4 variables.
concL < M < HpHL < M < HtempL < M < HheightA defoamer is a product that controls the formation of foam in industrial processes such as one might find in the food industry.
Peter R. Nelson, Marie Coffin and Karen A. F. Copeland (2003), Introductory Statistics for Engineering Experimentation, Elsevier. (Appendix A)
str(defoam)
dotplot(pH ~ height|conc, defoam, groups = temp, aspect = 0.3,
xlab = "Height of solution", type = c("p","a"),
auto.key = list(space = "right", lines = TRUE,
title = "Temperature"),
strip = FALSE, strip.left = TRUE,
ylab = "pH within concentration")
summary(fm1 <- lm(height ~ (conc + pH + temp)^2, defoam))
summary(fm2 <- lm(height ~ (pH + temp)^3, defoam))