George Mason University
Process Improvement
 

 

Rubric for Correction of Tukey Charts


 

This is the rubric used to correct the assignment on Tukey charts. 

Presentation

Corrections are needed if any of the following is present:

  1. The chart includes un-named labels such as "Series 1" and "Series 2."

  2. The markers in the control line were not removed.

  3. The chart does not have a title

  4. The X-axis does not have a title

  5. The Y-axis does not have a title

  6. The chart is not easy to find.

  7. The questions were answered in two separate files

  8. The questions were answered in the same worksheet

  9. Colors used in the chart and in the cell values, do not help in understanding of the work

  10. Except for the data, all cell values should be calculated as a formula.  Make sure that the moving range is calculated by formula.  Make sure that the control limits are calculated by formula.  If this is not the case, it is very important that you point this out.  You should be able to change a data value and all calculations should change automatically.

Accuracy 

Response to Question 1:

.
Time period 1 2 3 4 5 6 7 8
Observations 90 85 92 67 98 83 94 90
UCL 106.5 106.5 106.5 106.5 106.5 106.5 106.5 106.5
LCL 70.5 70.5 70.5 70.5 70.5 70.5 70.5 70.5
               
Sorted data                
67 Median 90            
83 1 quartile 84            
85 3 quartile 93            
90 Inter-quartile 9            
90 UCL 106.5            
92 LCL 70.5            
94                
98                

 

 

In the 4th period the health status had significant change.

 

Response to Question 2 

 

Day Minutes of exercise UCL Tukey LCL Tukey Sorted data    
1 25 52.5 0 0 Median 22
2 30 52.5 0 0 1 quartile 15
3 32 52.5 0 15 3 quartile 30
4 0 52.5 0 15 Inter-quartile 15
5 15 52.5 0 15 UCL 52.5
6 17 52.5 0 17 LCL -7.5
7 15 52.5 0 20    
8 40 52.5 0 24    
9 15 52.5 0 25    
10 28 52.5 0 28    
11 0 52.5 0 30    
12 60 52.5 0 32    
13 20 52.5 0 40    
14 24 52.5 0 60    

Day Minutes of exercise At least 30 minute exercise Duration of exercise UCL    
1 25 0 0 2.644994   Count
2 30 1 1 2.644994 Missed exercise 10
3 32 1 2 2.644994  30 min exercise 4
4 0 0 0 2.644994 R 0.4
5 15 0 0 2.644994 UCL 2.644994
6 17 0 0 2.644994    
7 15 0 0 2.644994    
8 40 1 1 2.644994    
9 15 0 0 2.644994    
10 28 0 0 2.644994    
11 0 0 0 2.644994    
12 60 1 1 2.644994    
13 20 0 0 2.644994    
14 24 0 0 2.644994    

 

 

Day Minutes of exercise UCL LCL Difference
1 25 74.69626 0  
2 30 74.69626 0 5
3 32 74.69626 0 2
4 0 74.69626 0 32
5 15 74.69626 0 15
6 17 74.69626 0 2
7 15 74.69626 0 2
8 40 74.69626 0 25
9 15 74.69626 0 25
10 28 74.69626 0 13
11 0 74.69626 0 28
12 60 74.69626 0 60
13 20 74.69626 0 40
14 24 74.69626 0 4
Average 22.92857     19.46154

 

 

Of all the three charts, only Tukey chart was able to detect points out of the control limits.  Tukey chart might be the most reasonable way of analyzing this data, it provides the tightest limits on the data.

 


Copyright © 1996 Farrokh Alemi, Ph.D. Most recent revision 09/04/2008.  This page is part of the course on Quality/Process Improvement.