2. [4 points] Assume that the diameter at breast height (in meters) of a sequoia tree is a normal random variable with mean 7.5 m and standard deviation 0.5 m. (a) Compute the probability that a sequoia tree will have a diameter at breast height that is larger than 9 m. (b) Compute the probability that a sequoia tree will have a diameter at breast height that is between 7 m and 9 m. (c) Find a value c such that 75% of the sequoia tree will have a di- ameter at breast height larger than c. (d) We select 6 sequoia trees at random, compute that probability that at least 5 of the 6 trees are going to have a diameter at breast height that is smaller than 9 m