A forest products company claims that the amount of usable lumber in its harvested trees averages 142 cubic feet and has a standard deviation of 9 cubic feet. Assume that these amounts have approximately a normal distribution. I. What percent of the trees contain between 133 and 169 cubic feet of lumber? Round to two decimal places. II. If 18,000 trees are usable, how many trees yield more than 151 cubic feet of lumber