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.

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)

Results

R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

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> library(datasets)
> png(filename="/home/ddbj/snapshot/RGM3/R_rel/result/datasets/warpbreaks.Rd_%03d_medium.png", width=480, height=480)
> ### Name: warpbreaks
> ### Title: The Number of Breaks in Yarn during Weaving
> ### Aliases: warpbreaks
> ### Keywords: datasets
> 
> ### ** Examples
> 
> require(stats); require(graphics)
> summary(warpbreaks)
     breaks      wool   tension
 Min.   :10.00   A:27   L:18   
 1st Qu.:18.25   B:27   M:18   
 Median :26.00          H:18   
 Mean   :28.15                 
 3rd Qu.:34.00                 
 Max.   :70.00                 
> 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))

Call:
lm(formula = breaks ~ wool * tension, data = warpbreaks)

Residuals:
     Min       1Q   Median       3Q      Max 
-19.5556  -6.8889  -0.6667   7.1944  25.4444 

Coefficients:
               Estimate Std. Error t value Pr(>|t|)    
(Intercept)      44.556      3.647  12.218 2.43e-16 ***
woolB           -16.333      5.157  -3.167 0.002677 ** 
tensionM        -20.556      5.157  -3.986 0.000228 ***
tensionH        -20.000      5.157  -3.878 0.000320 ***
woolB:tensionM   21.111      7.294   2.895 0.005698 ** 
woolB:tensionH   10.556      7.294   1.447 0.154327    
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 10.94 on 48 degrees of freedom
Multiple R-squared:  0.3778,	Adjusted R-squared:  0.3129 
F-statistic: 5.828 on 5 and 48 DF,  p-value: 0.0002772

> anova(fm1)
Analysis of Variance Table

Response: breaks
             Df Sum Sq Mean Sq F value    Pr(>F)    
wool          1  450.7  450.67  3.7653 0.0582130 .  
tension       2 2034.3 1017.13  8.4980 0.0006926 ***
wool:tension  2 1002.8  501.39  4.1891 0.0210442 *  
Residuals    48 5745.1  119.69                      
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>