ine distribution of the annual incomes of a group of middle-management employees at Compton Plastics approximates a normal distribution with a mean of $47,200 and a standard deviation of $800. (a) About 68% of the incomes lie between what two amounts? (b) About 95% of the incomes lie between what two amounts? (c) Virtually all of the incomes lie between what two amounts? (d) What are the median and the modal incomes? (e) Is the distribution of incomes symmetrical?