warpbreaks {datasets}R Documentation

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, New York, NY. Page 106.

References

McNeil D. (1977). Interactive Data Analysis: A Practical Primer. John Wiley & Sons. ISBN 978-0471026310.

Tukey J. W. (1977). Exploratory Data Analysis, number 2 series Addison-Wesley series in behavioral science. Addison-Wesley Publishing Company. ISBN 9780201076165.

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)

[Package datasets version 4.6.0 Index]