sushant_kulkarni
Involved In Discussions
Dear all,
Cpk used for Short term capability with Std. deviation with in sud-group variation.
Ppk used for Long term capabi;ity of system with Std. deviation from long time and actual process variation and sample size.
Though we are calculating Cpk or Ppk with system only stat. control then standard deviation for both the capability would be same?
How can Ppk will be less or standard deviation will be higher for Ppk.
Will it affect by common causes as well as special cause of variation?
and if it will be how can we say that system is in the stat. control?
If system isnot in the stat. control then to calulate Cpk and Ppk will be wrong.
Sushant
Cpk used for Short term capability with Std. deviation with in sud-group variation.
Ppk used for Long term capabi;ity of system with Std. deviation from long time and actual process variation and sample size.
Though we are calculating Cpk or Ppk with system only stat. control then standard deviation for both the capability would be same?
How can Ppk will be less or standard deviation will be higher for Ppk.
Will it affect by common causes as well as special cause of variation?
and if it will be how can we say that system is in the stat. control?
If system isnot in the stat. control then to calulate Cpk and Ppk will be wrong.
Sushant