Many authors instead compare separate P values for each subgroup, for example for younger and older participants. This approach leads to a considerable increase in the risk of Type I (false positive) ...

This example illustrates how to compute and display control limits for the maximum of a subgroup sample. Subgroup samples of 20 metal braces are collected daily, and the lengths of the braces are ...

A brewery monitors its bottling process to ensure that each bottle is filled with the proper amount of beer. The following data set contains the amount of beer recorded in fluid ounces for 23 batches: ...