battery {EngrExpt}

Battery lifetime in laptop computers

Description

Data from a study on the effect of different processors on the battery lifetime in laptop computers.

Format

A data frame with 30 observations on the following 2 variables.

type

processor type - a factor with levels A, B and C

lifetime

a numeric vector

References

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

Examples

str(battery)
densityplot(~ lifetime, battery, groups = type,
            xlab = "Battery lifetime (hours)",
            auto.key = list(columns = 3, lines = TRUE))
densityplot(~ lifetime, battery, groups = type,
            scales = list(x = list(log = 2)),
            xlab = "Battery lifetime (hours) - logarithmic scale",
            auto.key = list(columns = 3, lines = TRUE))
dotplot(reorder(as.factor(type), lifetime) ~ lifetime, battery,
        jitter.y = TRUE,
        xlab = "Battery lifetime (hours)",
        ylab = "Type", type = c("p", "a"))
dotplot(reorder(as.factor(type), lifetime) ~ lifetime, battery,
        jitter.y = TRUE, scales = list(x = list(log = 2)),
        xlab = "Battery lifetime (hours) - logarithmic scale",
        ylab = "Type", type = c("p", "a"))