Question 4 The diameters of screws in a batch are normally distributed with mean equal to 2 10 cm and standard deviation equal to 0 15 cm I a What proportion of screws are expected to have diameters greater than 2 50 cm 10 P b A specification calls for screw diameters between 1 75 cm and 2 50 cm What proportion of screws will meet the specification 15 P