how to remove random numbers generated if they are less than a certain value : <p>I'm generating random variates with <code>rnorm()</code> and need to remove any random variates that are less than 20.  </p>

<p>for example:</p>

<pre><code>rnorm(4, mean=30, sd=18)
[1] 18 25 36 16
</code></pre>

<p>needs to become: </p>

<pre><code>[1] 25 36
</code></pre>
