u Chart
- Last UpdatedMar 19, 2016
- 2 minute read
The following table contains the formulas used to calculate LCL and UCL for a chart point.
The example in the table illustrates the control limits calculated for a sample size of 15.
|
Formula |
Example |
|---|---|
|
CL = LCL = UCL = where n is the actual sample size from the sample. If LCL < 0, then LCL = 0; otherwise LCL |
CL = 0.55224 LCL = 0.45378 – (3 * LCL = 0 UCL = 0.55224 + (3 * |
The following table shows example control limits calculated for each chart point.
|
Label |
Chart Point (Defects Per Unit) |
Count |
Size |
LCL |
CL |
UCL |
Lower σ |
Upper σ |
|---|---|---|---|---|---|---|---|---|
|
1 |
0.2 |
3 |
15 |
0 |
0.552239 |
1.127863 |
0.184080 |
0.191875 |
|
2 |
0.888889 |
8 |
9 |
0 |
0.552239 |
1.295367 |
0.184080 |
0.247709 |
|
3 |
0.666667 |
10 |
15 |
0 |
0.552239 |
1.127863 |
0.184080 |
0.191875 |
|
4 |
0.4 |
6 |
15 |
0 |
0.552239 |
1.127863 |
0.184080 |
0.191875 |
|
5 |
0.133333 |
2 |
15 |
0 |
0.552239 |
1.127863 |
0.184080 |
0.191875 |
|
6 |
0.55 |
11 |
20 |
0.053734 |
0.552239 |
1.050744 |
0.184080 |
0.166168 |
|
7 |
0.6 |
9 |
15 |
0 |
0.552239 |
1.127863 |
0.184080 |
0.191875 |
|
8 |
0.333333 |
5 |
15 |
0 |
0.552239 |
1.127863 |
0.184080 |
0.191875 |
|
9 |
1.333333 |
20 |
15 |
0 |
0.552239 |
1.127863 |
0.184080 |
0.191875 |