3. A forest product company claims that the amount of usable lumber in harvested trees averages 172 cubic feet and has a standard deviation of 12.4 cubic feet. Assume the distribution have a normal distribution. Use the 63-95991 rule to answer the following. Answers a] When trees are harvested, what percent of trees contain more than 159.6 cubic feet of usable lumber? bl When trees are harvested, what percent of trees contain less than 1n cubic feet of usable lumber? c} of 2000 harvested trees, how mamr do we expect to have between 14?.2 and 195.8 cubic feet of usable lumber? d] When trees are harvested, what percent of trees contain less than 209.2 cubic feet of usable lumber? e) of 2000 harvested trees, how many do we expect to have between 134.8 and 184.4 cubic feet of usable lumber