According to a research firm, in U.S., the mean amount spent by a family of four on

Question:

According to a research firm, in U.S., the mean amount spent by a family of four on food per month is $500 with a standard deviation of $75. Assuming that the food costs are normally distributed, what is the probability that a randomly selected family of four spends less than $480 per month? (Round your answer to 4 decimal places.)