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<table width="100%" summary="page for warpbreaks"><tr><td>warpbreaks</td><td align="right">R Documentation</td></tr></table>

<h2>The Number of Breaks in Yarn during Weaving</h2>

<h3>Description</h3>


<p>This data set gives the number of warp breaks per loom, where a loom
corresponds to a fixed length of yarn.
</p>


<h3>Usage</h3>

<pre>warpbreaks</pre>


<h3>Format</h3>


<p>A data frame with 54 observations on 3 variables.
</p>

<table summary="Rd table">
<tr>
 <td align="right">
    <code>[,1]</code> </td><td align="left"> <code>breaks</code>  </td><td align="left"> numeric </td><td align="left"> The number of breaks</td>
</tr>
<tr>
 <td align="right">
    <code>[,2]</code> </td><td align="left"> <code>wool</code>    </td><td align="left"> factor  </td><td align="left"> The type of wool (A or B)</td>
</tr>
<tr>
 <td align="right">
    <code>[,3]</code> </td><td align="left"> <code>tension</code> </td><td align="left"> factor  </td><td align="left"> The level of tension (L, M, H)
  </td>
</tr>

</table>

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


<h3>Source</h3>


<p>Tippett, L. H. C. (1950)
<EM>Technological Applications of Statistics</EM>.
Wiley.  Page 106.
</p>


<h3>References</h3>


<p>Tukey, J. W. (1977)
<EM>Exploratory Data Analysis</EM>.
Addison-Wesley.
</p>
<p>McNeil, D. R. (1977)
<EM>Interactive Data Analysis</EM>.
Wiley.
</p>


<h3>See Also</h3>


<p><code>xtabs</code> for ways to display these data as a table.
</p>


<h3>Examples</h3>

<pre>
require(stats); require(graphics)
summary(warpbreaks)
opar &lt;- 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 &lt;- lm(breaks ~ wool*tension, data = warpbreaks))
anova(fm1)
</pre>


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