According to the National Retail Federation’s recent Back to College Consumer Intentions and Actions survey, families of college students spend an average of $616.13 on new apparel, furniture for dorms or apartments, school supplies, and electronics (www.nrf.com/modules.php?name=News&op=viewlive&sp_id=966). Suppose that the expenses on such Back to College items for the current year are approximately normally distributed with a mean of $616.13 and a standard deviation of $120. Find the probability that the amount of money spent on such items by a randomly selected family of a college student is
a. Less than $450
b. Between $500 and $750