Another important change is concerned with the F test in the ANOVA table of the full model, i.e., with interaction. The standard ANOVA table returned by R is for fixed effects, but an R&R study implies repeated measures, and therefore the error term (denominator of the F Statistic) should be the interaction one. Thus, the output of the ANOVA table has also changed to return the appropriate tests for the main effects (appraisal, part). What surprised me while checking the references, mainly the AIAG MSA Manual, which is one of the main sources for Six Sigma practitioners, is that in the example provided in page 127 repeatibility MS is used as error term, whilst in the appendix it is used the interaction MS (which is actually common practice in the rest of the references and commercial software).
By the way, I reviewed all the function code, included clearer comments, indentation, spaces, etc. Also a bug in the control limits of the range control chart has been corrected, along with some minor improvements.
I feel really encouraged to continue developing the package when receiving great feedback from people "working in industry where the grip of heavily commercialised software dominates, and feeling like lone warriors battling against this" ;-)
SixSigma package on github
SixSigma package on CRAN
Updates on sixsigmawithr.com
NOTE: It may take some days having the latest version on CRAN. If you read this before that happens, you can get the latest version from github running: