Step 1- Problem or Opportunity Statement
Living in metropolitan city like Jakarta is a hard work, everyday is moving from one place to another place. That’s why we need an efficient fuel consumption vehicle.
I want to know if my vehicle’s fuel consumption is within control or not.
Step 2 – “FEASIBLE alternatives”
Herewith my fuel consumption data for 25 days, everyday from home to office. My journey is around 50 km in return.
Step 3- Develop the outcomes for each alternative (minimum 2)
From data above, we can transform daily fuel usage into line chart:
Then, I calculated Mean and Standard Deviation. The result are:
Mean : 9.64 km/lt
Std dev : 1.15 km/lt
Step 4- Selection of the acceptable criteria
From Mean and Std dev, Upper Control Limit (UCL) and Lower Control Limit (LCL) is calculated, and we get:
Step 5- Analysis/ Comparison of the Alternatives against the Criteria
The green line shows UCL, while red line shows LCL. My fuel consumption in 25 days are below UCL and above LCL.
Step 6- Selection of the Best/ Preferred Alternative Compared against the Criteria
The UCL, LCL only tells you that the readings you have got are in statistically under control or not. So, from analysis, we knew that fuel consumption / gas mileage is statistically under control.
Step 7- Performance Monitoring and Post Evaluation of Result/ Follow up Assessment
Now that I already know my Control Limit, I can now analyze if my fuel consumption is not under control. Let’s say, if one day my gas mileage is 14 km/lt (above UCL), then I have to find out what is the cause. And I also have to maintain my car regularly.
These figure below, taken from http://www.doh.state.fl.us/hpi/pdf/Cause_and_EffectDiagram2.pdf, shows cause and effect diagram of Poor Gas Mileage:
Sullivan, William G., Wick, Elin M., Koelling, C. Patric. (2012), Engineering Economy. 15th ed., Pearson Higher Education, Inc.
Brassard, M and Ritter, D (2010), The Memory Jogger (2nd Edition), Canada, GOAL/QPC.
Giammalvo, PD. (2013). AACE Certification Preparation Course. Retrieved from http://www.build-project-management-competency.com/
Florida Health (). Basic Tools for Process Improvement; Module 5 ; Cause and Effect Diagram. [ONLINE] Available at: http://www.doh.state.fl.us/hpi/pdf/Cause_and_EffectDiagram2.pdf. [Last Accessed 28 September 2013].