A factory makes parts for laptop computers, including screws. The screws are required to have the right length. The lengths of the screws obey a normal distribution with mean μ=4.25 millimeters and standard deviation σ=0.022 millimeters.
Suppose a simple random sample of n = 20 screws is selected. Calculate the probability that their mean length is less than 4.26 millimeters.
Suppose a simple random sample of n = 20 screws is selected. Calculate the probability that their mean length is greater than 4.265 millimeters.