atory variable(s).</li>
</ol>
<p>For directing the computer, we write the model specification as a <strong>tilde expression</strong>: the name of the response variable goes to the left of the <img src="www/tilde.png" class="img-fluid" alt="tilde">. The name of the explanatory variable is on the right.</p>
<div class="page-columns page-full"><p>When there is more than one explanatory variable, their names all go on the right side of <img src="www/tilde.png" class="img-fluid" alt="tilde"> separated by the <co