How heavy a load (pounds) is required to pull apart pieces of Douglas fir four inches long and 1.5 inches square? Here are data from students doing the laboratory exercise: We are eager to regard wood pieces prepared for lab session as the SRS of all similar pieces of Douglas fir. Engineers also generally suppose that characteristics of materials vary Normally. Assume that strength of pieces of wood like these follows the Normal distribution with standard deviation 3000 pounds. (a) Is there important evidence at = 0.10 level against hypothesis that mean is 32,500 pounds for two-sided alternative? (b) Is there vital evidence at = 0.10 level against hypothesis that the mean is 31,500 pounds for two-sided alternative?