\BeginKnitrBlock{exercise}\iffalse{-91-65-115-115-101-115-115-105-110-103-32-99-114-101-100-105-98-105-108-105-116-121-93-}\fi{}<div class="exercise"><span class="exercise" id="exr:unnamed-chunk-75"><strong>(\#exr:unnamed-chunk-75)  \iffalse (Assessing credibility) \fi{} </strong></span></div>\EndKnitrBlock{exercise}