The width of a slot of a duralumin forging is (in inches) normally distributed with mean 0.9000 and standard deviation 0.0030. The specification limits were given as 0.9000 ± 0.0050. Note that °specification limits' are defined as the boundaries on the size of acceptable parts'

a. What percentage of forgings will be defective?

b. What is the maximum allowable valueof sigmas.gif that will permit no more than 1 in l00 defectives when the widths are normally distributed with mean0.9000 and standard deviation sigmas. gif