The average modulus of rupture (MOR) for a particular grade of pencil lead is known to be 6500 psi with a standard deviation of 250 psi. A random sample of size 16 is taken.
a. What is the sampling distribution of the mean?
b. What is the probability that the sample of 16 pencil leads will have an average MIR between 6400 and 6550 psi?
c. What assumptions did you make when answering the previous questions?