Data from a study of the repair time for different brands of computers in different configurations.
A data frame with 36 observations on the following 3 variables.
a factor with levels
an ordered factor with levels
Expensive home <
time to repair computer (minutes)
Peter R. Nelson, Marie Coffin and Karen A. F. Copeland (2003), Introductory Statistics for Engineering Experimentation, Elsevier. (Appendix A)
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str(computer) dotplot(type ~ time, computer, groups = brand, auto.key = list(columns = 3, lines = TRUE), type = c("p","a"), jitter.y = TRUE, xlab = "Time to repair computer (minutes)") summary(fm1 <- lm(time ~ brand * type, computer)) summary(fm2 <- lm(time ~ brand + type, computer)) summary(fm3 <- lm(time ~ type, computer))