www.6sigma.us
www.6sigma.us
No
Yes
Clerk B
137
26
121.73
41.27
Clerk BN
61
15
56.76
19.24
Clerk D
35
38
54.52
18.48
ERRORS
ERRORS
PREDICTED
PREDICTED
PREDICTED
12% better
Against Statistical
Predicted Value
7.5% better
35.9% worse
Observation
Clerk D causes higher than predicted errors
WHY?
Chi-Square Analysis