Suppose that engineering specifications on the shelf depth of a certain slug to be turned on a cnc lathe are from .0275 in. to .0278 in. and that values of this dimension produced on the lathe can be described using a normal distribution with mean μ and standard deviation σ . (a) if μ = .0276 and σ = .0001, about what frac- tion of shelf depths are in specifications? (b) what machine precision (as measured by σ ) would be required in order to produce about 98% of shelf depths within engineering spec- ifications (assuming that μ is at the midpoint of the specifications)?