\BeginKnitrBlock{exercise}\iffalse{-91-79-114-100-105-110-97-108-32-118-97-114-105-97-98-108-101-115-93-}\fi{}<div class="exercise"><span class="exercise" id="exr:unnamed-chunk-20"><strong>(\#exr:unnamed-chunk-20)  \iffalse (Ordinal variables) \fi{} </strong></span>Can you think of situation where age would be treated as a ordinal variable?</div>\EndKnitrBlock{exercise}