The mean amount spent by a family of four on food per month in U.S. is unknown,

Question:

The mean amount spent by a family of four on food per month in U.S. is unknown, but we assume that the distribution of the food costs is normal. A research firm selected 100 families and found that the mean amount is $500 with a standard deviation of $75. What is the probability that a randomly selected family of four spends less than $480 per month? (Round your answer to 4 decimal places.)

Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...