The medical records of infants delivered at Kaiser Memorial Hospital show that the infants' lengths at birth (in inches) are normally distributed with a mean of 18 and a standard deviation of 2.4. Find the probability that an infant selected at random from among those delivered at the hospital measures the following. (Round your answers to four decimal places.)

(a) more than 19 in.

(b) less than 17 in.

(c) between 15 and 21 in.