\BeginKnitrBlock{exercise}\iffalse{-91-84-119-111-45-115-105-100-101-100-32-116-101-115-116-115-93-}\fi{}<div class="exercise"><span class="exercise" id="exr:unnamed-chunk-78"><strong>(\#exr:unnamed-chunk-78)  \iffalse (Two-sided tests) \fi{} </strong></span>Can you think of a two--sided weather problem?</div>\EndKnitrBlock{exercise}