b. Which measure of center bener describes the typical number of hours the seniors work per week? Explain. 4. The following cumulative relative frequency graph displays the distribution of the lifetime (in hours) of a AA battery. 1 9 Lifetimes of AA Batteries (hrs) T L +1 1 0.8 "0.71+1 TT 10.6 T V e 0.5 T L 0.4 r 1 0.3 + 0.2 0.1 T r 0 74 e 150 175 200 225 250 275 300 325 350 375 400 Battery Life (in hours) (a) Approximately what percent of the batteries will last fewer than 250 hours? Approximately what proportion of batteries will last 325 hours or more?