deink dataset

1.1

data

De-inking of newsprint

Format

A data frame with 27 observations on the following 3 variables.

• alkali: amount of alkali in the solution
• hardness: hardness of the water - an ordered factor with levels 50 < 150 < 250
• bright: a measure of brightness

References

Peter R. Nelson, Marie Coffin and Karen A. F. Copeland (2003), Introductory Statistics for Engineering Experimentation, Elsevier. (Appendix A)

Details

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.

Examples

str(deink)
xtabs(~ alkali + hardness, deink)
dotplot(hardness ~ bright, deink, groups = alkali,
        auto.key = list(columns = 3, lines = TRUE),
        type = c("p","a"), aspect = 'xy',
        xlab = "Brightness by amount of alkali",
        ylab = "Hardness of the water")