The width of a slot of a duralumin forging is (in inches) normally distributed with u = 0:900 and ? = 0:003. The speci cation limits were given as 0:900 0:005. (a) What percentage of forgings will be defective? (b) What is the maximum allowable value of that will permit no more than 1 in 100 defectives when the widths are normally distributed with u= 0:900 and ??