A forestry company planted a population of Douglas fir trees 30 years ago. Today, the trunk diameters of these trees have a mean of 6.87 inches and a standard deviation of 1.07 inches.
A forestry company planted a population of Douglas fir trees 30 years ago. Today, the trunk
diameters of these trees have a mean of 6.87 inches and a standard deviation of 1.07 inches.
a. Suppose you randomly sample 40 of these fir trees and measure their trunk diameters.
What is the probability of getting a sample mean diameter greater than 7.5 inches?
b. Did you need to assume anything about the shape of the distribution of trunk diameters
for your calculation in part (a)? If so, what must be assumed? If not, explain why