Statistics from Cornell’s Northeast Regional Climate Center indicate that Ithaca

Statistics from Cornell’s Northeast Regional Climate Center indicate that Ithaca, NY, gets an average of 35.4" of rain each year, with a standard deviation of 4.2".

Assume that a Normal model applies.

a) During what percentage of years does Ithaca get more than 40" of rain?
b) Less than how much rain falls in the driest 20% of all years?
c) A Cornell University student is in Ithaca for 4 years. Let y¯. represent the mean amount of rain for those 4 years. Describe the sampling distribution model of this sample mean, y¯.
d) What’s the probability that those 4 years average less than 30" of rain?