d="fig-quant-cat-caption-0ceaefa1-69ba-4598-a22c-09a6ac19f8ca">
Figure&nbsp;10.8: Mapping the quantitative explanatory variable to the horizontal axis.
</figcaption>
</figure>
</div>
</div>
</div>
<p><strong>Two quantitative explanatory variables</strong></p>
<p>This example draws on the same data frame as the previous two examples, but we use the mother’s and father’s heights for the explanatory variables. Both these explanatory variables are quantitative.</p>
<div class="cell">
<div class="sourceCode 