Question Help Steel rods are manufactured with a mean length of 21 centimeter (cm). Because of variability in the manufacturing process, the lengths of the
rods are approximately normally distributed with a standard deviation of 0.07 cm.
(a) what proportion of rods has a length less than 20.9 cm?
(b) any rods that are shorter than 20. 83 cm or longer than 21. 17 cm are discarded. What proportion of rods will be discarded?
(c) using the results of part (b), if 5000 rods are manufactured in a day, how many should the plant manager expect to discard?
(d) if an order comes in for 10,000 steel rods, how many rods should the plant manager expect to manufacture if the order states that all rods must be between 20.9 cm in 21.1 cm?