1. Other Useful Tools for Statistical Process Control (aka “The Magnificent Seven”)

2. Class Schedule Today: new content (will be on exam)
Tuesday, Sept 30th: Exam review
Bring your formula sheet
Thursday, Oct 2nd: Exam!
Tuesday, Oct 7th: No class!
Can attend career fair during class time
I will hold office hours (5262 SAS) during class time if you have questions

3. Announcement: Sciences Career Fair
October 7th from 10:00-3:00 at Tally
careers.ncsu.edu/events-and-career-fairs/sciences-career-fair/
Notes:
Dress Professionally
Bring multiple copies of your resume
Bring your student ID  
Questions? Contact Career Development Center ( ) or Jenna Hartwell

4. Magnificent Seven Seven major tools for SPC
Histogram or stem and leaf plot
Check sheet
Pareto chart
Cause and effect diagrams
Defect concentration diagram
Scatter diagram (scatterplot)
Control chart

5. Control Charts: The “Big Idea”
Monitor process output
If variability in process is just random sampling variability, values should be within control limits
If other sources are present then values may be beyond control limits

6. Recall: Sources of variability
Common Causes
Random/chance variation
Process is stable
Assignable Causes
Process shifts or becomes more varied
Variability in process that comes from specific causes
Can (and need to) be identified and removed

7. Cause and effect diagrams
Identify assignable sources of variability
Also called Ishikawa or “Fishbone” diagrams

8. Cause and effect diagrams
Define the problem to be analyzed
Create a group with knowledge of the process that can draw the diagram
Diagram components:
A horizontal arrow with the problem to be studied in a box on the right.
Major branches with main causes.
Additional arrows within each major branch with secondary causes. 

9. Cause and effect diagrams
Result (i.e. the problem)

10. Cause and effect diagrams
Major factor 2
Major factor 3
Major factor
Result (i.e. the problem)
Major factor 4
Major factor 5

11. Cause and effect diagrams
Major factor 2
Major factor 3
Major factor
Result (i.e. the problem)
Sub- factor
Sub- factor
Sub- factor
Sub- factor
Sub- factor
Sub- factor
Major factor 4
Major factor 5

12. Example cause and effect diagram

13. Example cause and effect diagram
Can’t be controlled

14. Questions for you

15. Pareto chart Bar chart of attribute data Arranged in frequency order
Target most common problem for improvement
Caution: Most common problem is not necessarily most important problem

16. Example Statistics exam 20 multiple choice questions
Which topic missed most?

17. Example Pareto chart

18. Example Pareto chart

19. Pareto chart Bar chart of attribute data Arranged in frequency order
Target most common problem for improvement
Caution: Most common problem is not necessarily most important problem
Solution: Create Pareto chart of cost or importance to accompany frequency chart

20. Histogram or Stem and leaf plot
Explore distribution of a variable
Histogram better for large datasets
Stem and leaf (or dotplot) better for smaller datasets

21. Check Sheet Written checklist of defects
By type, locations, or cause (e.g. machine, worker)
Ordered by time to observe trends
Could be used for data collection/entry to then create other charts
E.g. control chart, Pareto chart

22. Example Check Sheet

23. Defect concentration diagram
Picture of unit that shows all relevant views (e.g. front, back, sides, top, bottom)
Shows location of defects
May point to cause of defects
Ex: Lever used to move unit on assembly line has a worn pad

24. Example defect concentration diagram

25. Example defect concentration diagram
DE, SC DE

26. Scatterplot Explore relationship between two variables
Between possible assignable cause and output
Overall form of relationship
Linear or not
Direction of relationship
Positive or negative
Strength of relationship
How tightly clustered together are the points?

27. Example scatterplots Strong, positive relationship No relationship
Weaker, negative
relationship