warpbreaks | 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)
```