The plotted points represent the number of defects in each subgroup, .
The center line represents the process mean, . If you do not specify a historical value, then Minitab uses the mean from your data,
, to estimate
.
Term | Description |
---|---|
![]() | number of defects in subgroup ![]() |
![]() | number of subgroups |
The LCL is the greater of the following:
Term | Description |
---|---|
![]() | process mean |
![]() | parameter for Test 1. The default is 3. (For more information go to Select tests for special causes for C Chart.) |