 Different Root Stocks</h2>

<h3>Description</h3>

<p>In a classic experiment carried out from 1918 to 1934, growth of apple trees
of six different rootstocks were compared on four measures of size.
How do the measures of size vary with the type of rootstock?
</p>


<h3>Format</h3>

<p>A data frame with 48 observations on the following 5 variables.
</p>
 
<dl>
<dt><code>rootstock</code></dt><dd><p>a factor with levels <code>1</code> <code>2</code> <code>3</code> <code>4</code> <code>5</code> <code>6</code><