1. Find out the value of z such that 45% of the distribution lies between it and mean.
2. Suppose that the average annual salary for the worker in the United States is $31,000 and that annual salaries for Americans are normally distributed with the standard deviation equal to $7,500. Find out the following:
a) What percentage of the Americans earn below $20,000?
b) What percentage of the Americans earn above $45,000?