vitamin {EngrExpt}R Documentation

Calcium levels before and after vitamin supplement

Description

Calcium levels before and after vitamin supplement

Format

A data frame with 49 observations on the following 3 variables.

treatment
formulation - a factor with levels A, B and C
before
Calcium level before the vitamin
after
Calcium level after the vitamin

References

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

Examples

str(vitamin)
summary(vitamin)
show(plt1 <- xyplot(after ~ before, vitamin, groups = treatment,
       auto.key = list(space = "right", title = "Formulation", lines = TRUE),
       aspect = "iso",
       type = c("g","p","smooth"),
       xlab  = "Calcium level before the vitamin",
       ylab = "Calcium level after the vitamin"))
tmd(plt1, aspect = 1)
densityplot(~ I(after - before), vitamin, groups = treatment,
            auto.key = list(columns = 3, lines = TRUE),
            xlab = "Change in calcium level after taking vitamin")

[Package EngrExpt version 0.1-8 Index]