Query on checkbox's in transaction QGC1

Dear Experts,

I would like to know the what is the functionality of the  below check box's in control charts transaction QGC1 under the western electric rules

1.       1 point outside 3-sigma

2.       2 from 3 points outside 2 sigma

3.       4 from 5 points outside 1 sigma

4.       8 points above / below mean value

5.       15 points within +/- 1-sigma

6.       6 points in ascending/descending order

7.        Immediate check of limit violations

I checked in sap.help document but couldn't understand the functionality of these check boxes. Please provide me an overview on these check boxes.

J.Balakrishnan