3-5 Homework: Chapter 2
Jennifer Liu
QSO-60Q5619-Operations Management
Southern New Hampshire University
Professor Dr. Zivick
August 2, 2015

Question: 2-52

CAUSE AND EFFECT DIAGRAM

Operator Mechanical Electrical

Car will not start
Car will not start

Fuel System Environment

Question: 2-52 When developing a fishbone diagram for the possible causes of your car not starting, it is important to list all ideas of possible cause. One all the possible causes have been listed you can start to eliminate non-causes of the problem. For example, on my list one possible cause is lost key. However, if we have the key to the car then we can eliminate lost key from our diagram knowing that is no longer a likely cause of reason for the car not starting. When eliminating a possible cause, it is still best to leave it on the diagram by just crossing it out and not removing it. This allows you to return at a later time to determine if you have eliminated true causes of the problem (Dr. McNeese, n.d.). The next step would be to determine how likely each idea is an actual cause of the problem. You can do this by adding notes to each idea such as (v) very likely, (s) somewhat likely, and (n) not likely. For example, if you put gas in the car yesterday and you know the possibility of no gas is not likely, you would put (n) next to no gas eliminating that possibility (Dr. McNeese, n.d.).

Problem: 2.52 The Omega Shoe Company manufactures a number of different styles of athletic shoes. Its biggest seller is the X-Pacer running shoe. In 2008 Omega implemented a quality-management program. The company's shoe production for the past three years and manufacturing costs are as follows. Year 2008 2009 2010 Units produced/input 32,000 34,600 35,500 Manufacturing cost $278,000 291,000 305,000 Percent good quality 78% 83% 90% Manufacturing cost per good product: 2008: Yield = 32,000(0.78) + 32,000(0.22) (0.25) = 24,960 + 1,760 = 26,720 Product cost per unit = (278,000 + 3520) ÷ 26,720 = $10.54 2009: Yield = 34,600(0.83) + 34,600(0.17) (0.25) = 28,718 + 1,470.50 = 30,188.50 Product cost per unit = (291,000 + 2,941) ÷ 30,188.50 = $9.74 2010: Yield = 35,500(0.9) + 35,500(0.1) (0.25) = 31,950 + 887.50 = 32,837.50 Product cost per unit = (305,000 + 1,775) ÷ 32,837.50 = $9.34 Percentage Change: 2008 – 2009: (10.54-9.74)/10.54*100 = 7.6% decrease 2009 – 2010: (9.74-9.34)/9.74*100 = 4.1% decrease Overall decrease (10.54-9.34)/10.54*100 = 11.38%

Problem 2-6 The Colonial House Furniture Company: Stage Average Percentage Good Quality 1 87% 2 91% 3 94% 4 93% 5 93% 6 96% a. The weekly product yield for good quality cabinets = product input *0.87*0.91*0.94*.093*0.93*0.96 = 300*0.618 = 185.4 b. In order to achieve a final weekly product yield of 300 cabinets, the weekly product input + 300/(0.87*0.91*0.94*0.93*0.93*0.96) = 300/0.618 = 485.4

References: Dr. McNeese, Bill (n.d.) Analyzing Cause and Effect Diagrams Retrieved from: http://www.spcforexcel.com/knowledge/root-cause-analysis/analyzing-cause-and-effect-diagrams Russell, R., & Taylor, B. (2014) The effect of Quality Management on Productivity. Operations and Supply Chain Management (8th ed. ed) Hoboken, NJ: John Wiley & Sons (chapter 2)