A forester measured 23 of the trees in a large woods that is up for sale. He found a mean diameter of 10.9 inches and a standard deviation of 4.2 inches. Suppose that these trees provide an accurate description of the whole forest and that a Normal model applies. a) Choose the correct Normal model for tree diameters. OA Q G M-20 16%6 68% 60% -20 95% +20 99.75 +36 17 25 67 10 11 103 215 -17 25 67 109 151 193 235 b) What size would you expect the central 95% of all tree diameters to be? Using the 68-95-99.7 rule, the central 95% of the tree diameters are between inches and inches. (Do not round. Type integers or decimals.) OC 90% 97% 109 151 193 215