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)
[,3]	tension	factor	The level of tension (L, M, H)

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

Source

Tippett, L. H. C. (1950) Technological Applications of Statistics. Wiley. Page 106.

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

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)