I've noticed that the calculated Cpk in DataPage does not match what is calculated in Minitab on the same data set. We don't use DataPage except to collect data, but I'd like to preview statistical analysis before sending the data. Is this common? Are there different methods of calculating Cpk?
I've noticed that the calculated Cpk in DataPage does not match what is calculated in Minitab on the same data set. We don't use DataPage except to collect data, but I'd like to preview statistical analysis before sending the data. Is this common? Are there different methods of calculating Cpk?
Check the DP settings.
OPTIONS
SPC CALCULATIONS
CAPABILITY THRESHOLDS
DP & Excel Cpk match when using 4 sigma, 1.33 for the value (I think these are DP defaults)
However, check to see WHICH Cap Calc Rules are used. Mark the "Use estimated std. dev for Cp Cpk, etc. Use Sample std. dev for Pp, Ppk, etc." I have a feeling the other option may be checked, which sets Pp, Ppk, etc. to sample std dev.
I've noticed that the calculated Cpk in DataPage does not match what is calculated in Minitab on the same data set. We don't use DataPage except to collect data, but I'd like to preview statistical analysis before sending the data. Is this common? Are there different methods of calculating Cpk?
Check the DP settings.
OPTIONS
SPC CALCULATIONS
CAPABILITY THRESHOLDS
DP & Excel Cpk match when using 4 sigma, 1.33 for the value (I think these are DP defaults)
However, check to see WHICH Cap Calc Rules are used. Mark the "Use estimated std. dev for Cp Cpk, etc. Use Sample std. dev for Pp, Ppk, etc." I have a feeling the other option may be checked, which sets Pp, Ppk, etc. to sample std dev.
