Detecting sustained shift sizes using a CUSUM

This macro can be used along with a CUSUM chart to estimate the size of a small, sustained shift in a process mean. This shift size is also expressed in terms of the within-subgroup sigma estimate.

Download the Macro

Be sure that Minitab knows where to find your downloaded macro. Choose File > Options > General. Under Macro location browse to the location where you save macro files.

Important

If you use an older web browser, when you click the Download button, the file may open in Quicktime, which shares the .mac file extension with Minitab macros. To save the macro, right-click the Download button and choose Save target as.

Download SHIFTSIZE.mac

Required Inputs

A column of data
The subgroup size
The target value
The numbers of the first and last subgroup where you suspect the shift

Running the Macro

Suppose your data are in C2, the subgroup size is 5, and the target is 25. You suspect that there is a process shift that starts in subgroup 19 and ends at subgroup 30. To run the macro, choose View > Command Line/History and type:

%SHIFTSIZE C2 5 25 19 30

Click Run.