ty-13-area-data-v" class="anchor-section" aria-label="Anchor link to header"></a></h1>
<p><em>NOTE</em>: The source files for this book are available with companion package <a href="https://paezha.github.io/isdas/">{isdas}</a>. The source files are in Rmarkdown format and packed as templates. These files allow you execute code within the notebook, so that you can work interactively with the notes.</p>
<div id="practice-questions-10" class="section level2 hasAnchor" number="28.1">
<h2><span class="header-sec