An automatic grinding machine in an auto parts plant prepare axles with a target diameter millimeters. The machine has some variability, so the standard deviation of the diameters is mm. Assume that the distribution of diameters is approximately normal.
(a). What proportion of parts made by this machine will have a diameter in between 40.122 and 40.128?
(b). A part will be randomly selected for inspection. What is the probability that the part selected will have a diameter smaller than 40.121?

Question

An automatic grinding machine in an auto parts plant prepare axles with a target diameter ￼ millimeters. The machine has some variability, so the standard deviation of the diameters is ￼  mm. Assume that the distribution of diameters is approximately normal.
(a). What proportion of parts made by this machine will have a diameter in between 40.122 and 40.128?
(b). A part will be randomly selected for inspection. What is the probability that the part selected will have a diameter smaller than 40.121?