he production of pipes has a mean diameter of 3.25 inches and a standard deviation of .15 inches. The shape of the distribution is approximated by a normal distribution since approximately an equal number of parts are above or below average, and most parts are very close to the mean value. A part will be discarded is it has a diameter of greater than 3.5 inches or less than 3 inches. What proportion of parts are discarded from the production line