o binarize this variable into <code>ozone1</code> (top 10% take 1 and 0 otherwise), <code>ozone2</code> (top 20% take 1 and 0 otherwise), and <code>ozone3</code> (top 30% take 1 and 0 otherwise).</p>
<div class="sourceCode" id="cb8"><pre class="sourceCode r"><code class="sourceCode r"><a class="sourceLine" id="cb8-1" data-line-number="1"><span class="co"># delete observations having NAs </span></a>
<a class="sourceLine" id="cb8-2" data-line-number="2">ozonedat &lt;-<span class="st"> </span><span class="kw">