Calcium levels before and after vitamin supplement
Calcium levels before and after vitamin supplement
A data frame with 49 observations on the following 3 variables.
treatmentformulation - a factor with levels A,
B and C
beforeCalcium level before the vitamin
afterCalcium level after the vitamin
Peter R. Nelson, Marie Coffin and Karen A. F. Copeland (2003), Introductory Statistics for Engineering Experimentation, Elsevier. (Appendix A)
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")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.