The amount of fill in a half-liter (500 ml) soft drink bottle is normally distributed

The amount of fill in a half-liter (500 ml) soft drink bottle is normally distributed. The process has a standard deviation of 4.0 ml. The mean is adjustable.

(a) Where should the mean be set to ensure a 95 percent probability that a half-liter bottle will not be underfilled? (Round your answer to 2 decimal places.)

(b) Where should the mean be set to ensure a 99 percent probability that a half-liter bottle will not be underfilled? (Round your answer to 2 decimal places.)

(c) Where should the mean be set to ensure a 99.9 percent probability that a half-liter bottle will not be underfilled? (Round your answer to 2 decimal places.)