#### Subgroup Parameters

The Control dialog box lets you set the minimum and maximum number of subgroups as well as the subgroup size.

To access this dialog box, choose Tools | Calculations. Then click the Subgroup Parameters button from the Calculation Specification dialog box.

Control dialog box

Min Subgroups - Use this field to select the minimum number of subgroups required to perform statistical analyses and produce a DataPage+ Statistics Report, Bar & Whisker Chart, or Process Chart. If you try to create one of these charts or the Statistics Report for a number of transactions less than the subgroup size multiplied by the minimum number of subgroups, DataPage+ will display an error that says, "There are not enough points to create at least 3 subgroups of size 3."

Max Subgroups - Use this field to select the maximum number of subgroups that may be used to perform statistical analysis and produce a DataPage+ Statistics Report, Bar & Whisker Chart, or Process Chart. If, when creating the report or chart, you select a number of subgroups that exceeds the maximum number you enter here, the report or chart will include only the most recent subgroups. For example, if you enter 10 here and you select 14 subgroups for processing, the report or chart will include the ten subgroups with the most recent transaction dates and times and will exclude the other four.

Subgroup Size - This field sets the subgroup size (that is, the number of individual observations per subgroup). For example, if you typically sample five parts from a process at a single time, enter 5 as the subgroup size.