| bright {EngrExpt} | R Documentation |
One step of recycling newsprint is to "de-ink" the newsprint, that is to remove the ink. The brightness of the paper pulp after a de-inking process is a measure of how well the process to remove the ink worked. A half-fraction of a 2^5 factorial experiment experiment was run to test various factors on the ability to de-ink newsprint.
data(bright)
A data frame with 16 observations on the following 6 variables.
typeA < BpercenttimehardnessspeedS < FbrightPeter R. Nelson, Marie Coffin and Karen A. F. Copeland (2003), Introductory Statistics for Engineering Experimentation, Elsevier. (Appendix A)
str(bright)
options(contrasts = c("contr.treatment", "contr.helmert"))
summary(fm1 <- lm(bright ~ (type + percent + time + hardness + speed)^2,
bright))
qqmath(coef(fm1)[-1], aspect = 1,
panel = function(...)
{
panel.grid(h = -1, v = -1)
panel.qqmath(...)
panel.qqmathline(..., alpha = 0.5, lty = 2)
},
xlab = "Standard normal quantiles",
ylab = "First- and second-order effects")
summary(fm2 <- lm(bright ~ (type + hardness)^2, bright))
dotplot(type ~ bright, bright, groups = hardness,
type = c("p", "a"), jitter.y = TRUE,
xlab = "Brightness of pulp (lines and point styles are levels of water hardness)",
ylab = "Alkali type", aspect = 0.4,
auto.key = list(lines = TRUE, columns = 2))