Notes and Considerations
These notes are from a Q&A exchange with a StatSoft statistician regarding using Statistica to create a CUSUM chart.
Questions/comments:
Attached is a .pdf file with excerpts from the Montgomery text regarding CUSUM tabular output. The specific output is listed in Table 8-2 on page 392. I would like to know if this is output that Statistica provides.
I used the Statistica CUSUM product during the course I mentioned, and found that I may also have questions regarding exactly how to specify values for "h" and "k" (see page 395). I believe that I've figured out where to specify 'mu0".
The following notes are responses to the questions:
Attached is a workbook where I recreated the example data set from the text and reproduced the results. STATISTICA will give you the same results as the text; things are calculated the same way. We specify mu as center and sigma as sigma on the X(MA) specs tab. Also on this tab, you can also specify h. The default in STATISTICA is 5. To make modifications, select UCL and LCL.
More info:
Statistica does not offer the V-mask functionality. However, it does provide the underlying tables which are more informative.
There is also an attached document ("Cusum how-to instructions from StatSoft.doc") that has instructions and explanation from StatSoft.
Data Set
The data set is contained within the Statistica workbook attached below. (Statistica CuSum.stw)
The data set is based on the example in the Montgomery SQC text regarding CUSUM tabular output. The specific output is listed in Table 8-2 on page 392. See the file "Chapter_8_Examples.xls" attached to the Statistical Quality Control (Montgomery) page.
Analysis or Script File
See "Statistica CuSum.stw" attached below.