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. 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)

[Package datasets version 3.3.2 Index]