According to Bureau of Labor Statistics data, the average income for a worker in the metropolitan Boston area is $65,420. Suppose average income for a worker in the metropolitan Boston area is normally distributed with a standard deviation of $4,246. A metropolitan Boston area worker is randomly selected.
a. What is the probability that the worker’s income is more than $72,000?

b. What is the probability that the worker’s income is less than $60,000?
c. What is the probability that the worker’s income is more than $55,000?
d. What is the probability that the worker’s income is between $57,000 and $68,000?