The heights of pecan trees are normally distributed with a mean of 10 feet and a standard deviation of 2 feet. *show all work- work with without supporting information will receive no credit**

a) What is the probability that a randomly selected pecan tree is between 9 and 12 feet tall? (round to 4 decimal places)

b) Find the 75th percentile of the pecan tree height distribution. (round to 2 decimal places)

c) for a sample of 64 pecan trees, state the standard deviation of the sample mean (or "standard error") Round to three decimal places.

d) Suppose a sample of 64 pecan trees is taken. Find the probability that the sample mean heights is between 9.5 and 10 feet (round to 4 decimal places).