h2>

<h3>Description</h3>

<p>A classical N, P, K (nitrogen, phosphate, potassium) factorial
experiment on the growth of peas conducted on 6 blocks. Each half of a
fractional factorial design confounding the NPK interaction was used
on 3 of the plots.
</p>


<h3>Usage</h3>

<pre><code class='language-R'>npk
</code></pre>


<h3>Format</h3>

<p>The <code>npk</code> data frame has 24 rows and 5 columns:
</p>

<dl>
<dt><code>block</code></dt><dd>
<p>which block (label 1 to 6).
</p>
</dd>
<dt><code>N</code></dt>