this case, the code
chunk has the option <code>include=FALSE</code>, which means neither the code or its result
will be displayed in the finished document. Other frequently used <code>TRUE/FALSE</code>
options are:</p>
<ul>
<li><code>eval</code>: when set to <code>FALSE</code>, the code will not be run when knitting the
document (default is <code>TRUE</code>);</li>
<li><code>echo</code>: when set to <code>FALSE</code>, the code will not show up in the document but
it will be run under the hood and its resul