datasets (version 3.6.2)

warpbreaks: The Number of Breaks in Yarn during Weaving

Description

This data set gives the number of warp breaks per loom, where a loom corresponds to a fixed length of yarn.

Usage

warpbreaks

Format

A data frame with 54 observations on 3 variables.

[,1]	breaks	numeric	The number of breaks
[,2]	wool	factor	The type of wool (A or B)

There are measurements on 9 looms for each of the six types of warp (AL, AM, AH, BL, BM, BH).

References

Tukey, J. W. (1977) Exploratory Data Analysis. Addison-Wesley.

McNeil, D. R. (1977) Interactive Data Analysis. Wiley.

See Also

xtabs for ways to display these data as a table.

Examples

# NOT RUN {
require(stats); require(graphics)
summary(warpbreaks)
opar <- par(mfrow = c(1, 2), oma = c(0, 0, 1.1, 0))
plot(breaks ~ tension, data = warpbreaks, col = "lightgray",
     varwidth = TRUE, subset = wool == "A", main = "Wool A")
plot(breaks ~ tension, data = warpbreaks, col = "lightgray",
     varwidth = TRUE, subset = wool == "B", main = "Wool B")
mtext("warpbreaks data", side = 3, outer = TRUE)
par(opar)
summary(fm1 <- lm(breaks ~ wool*tension, data = warpbreaks))
anova(fm1)
# }