Week 7 : Quality Control and Inventory Management - Quiz Solution 1. prevention, appraisal, internal failure, and external failure 2. Statistical process control (SPC) 3.uncertainty about when customers will order products. 4.internal failure costs. 5. $30,000 decrease 6. order delivery time 7. Carrying costs 8 Both A and C are correct. 9 smaller EOQ amounts 10 $2,400..