#### Control Tests

The Configure Tests dialog box determines what control tests are applied to data and the number of points required for passing/failing certain tests.

To access this dialog box, choose Tools | Calculations. Then click Control Tests from the Calculation Specification dialog box.

Configure Tests dialog box

Sometimes referred to as Western Electric Tests or AT&T Tests, these ten tests (numbered T1 to T10 in the graphic below) test for unnatural patterns that indicate the process may be out of control. AT&T tests are performed on individual observations and ranges and subgroup means and ranges.

The following tests are available. You can choose the number of points required for passing/failing T1 through T9:

T1 When this test is applied, the process is considered out of control if one point falls outside the 3 sigma limit. The default number 1 can be changed to any number from 1 to 99. | T6 When this test is applied, the process is considered out of control if eight successive points fall beyond either one sigma limit (mixture). The default number 8 can be changed to any number from 1 to 99.
T2 When this test is applied, the process is considered out of control if two of three successive points fall beyond the same two sigma limit. The default numbers 2 and 3 can be changed to any numbers from 1 to 99. | T7 When this test is applied, the process is considered out of control if eight successive increasing or decreasing points exist, indicating significant distribution shifts. The default number 8 can be changed to any number from 1 to 99.
T3 When this test is applied, the process is considered out of control if four of five successive points fall beyond the same one sigma limit. The default numbers 4 and 5 can be changed to any numbers from 1 to 99. | T8 When this test is applied, the process is considered out of control if 40 percent or less of the number of subgroups fall in the middle third of the control chart. The default number 40 can be changed to any number from 1 to 99.
T4 When this test is applied, the process is considered out of control if eight successive points fall on one side of the center. The default number 8 can be changed to any number from 1 to 99. | T9 When this test is applied, the process is considered out of control if more than 90 percent of the number of subgroups fall in the middle third of the control chart. The default number 90 can be changed to any number from 1 to 99.
T5 When this test is applied, the process is considered out of control if 15 successive points fall within one sigma limit (stratification). The default number 15 can be changed to any number from 1 to 99. | T10 When this test is applied, the process is considered out of control if the number of center line crossings does not fall between the calculated allowable minimum and maximum. This test is not configurable.

To Configure and Apply AT&T Tests:

1. Access the Configure Tests dialog box.

2. Modify the values in the different boxes as needed.

3. Select and clear the Individual and Range check boxes to apply the test to individual observations and to subgroup means and ranges as desired.

4. Click OK to save your changes.

To View AT&T Test Results:

You can view the results of applied AT&T tests can be viewed for reports or applicable charts by doing the following:

1. Click on the Chart tab.

2. Select the Change charts type icon from the toolbar.

3. Select the AT&T Test Chart.

See "AT&T Test Chart".

Save - Saves the currently defined items on the dialog box for subsequent sessions. When you log back into Datapage+ at a later time, the software will used this saved configuration.

Default - Loads the default configuration.

OK - Applies the current configuration until the end of your current session. When you log back into Datapage+, the software will use the saved configuration (or the default configuration if no saved configuration exists).

Cancel - Closes this dialog box.