Examine the sample obtained from a normally distributed population:

a. Calculate the variance.
b. Calculate the probability that a randomly chosen sample would produce a sample variance at least as large as that produced in part a if the population variance was equal to 20.
c. What is the statistical term used to describe the probability calculated in part b?
d. Conduct a hypothesis test to determine if the population variance is larger than 15.3. Use a significance level equal to 0.05.