4. The specifications for the thickness of nonferrous washers are 1.00.04mm. From process data, the distribution of the washer thickness is estimated to be normal with a mean of 0.98mm and a standard deviation of 0.02mm. The unit cost of rework is $0.10, and the unit cost of scrap is $0.15. For a daily production of 10,000 items: T total 20pts ) a) What proportion of the washers is conforming? What is the expected total daily cost of rework and scrap? (10pts) b) The manufacturer is trying to improve the process and reduces its standard deviation to 0.015mm. If the process mean is adjusted at 1.0mm, what is the percent decrease in the expected total daily cost of rework and scrap compared to that of part (a)? (10pts)