Hi All,

I just newly joined this discussion topic. Can anybody share with me why Motorola wants to use 1.5 sigma shift to replace original statistical concept of 6 sigma is based on plus and minus 3 sigma ?

I read few sigma books but not really mentioning on why and is it valid with such a shift. What is the rationale with such a shift and it is stastical proven based on the Gausian Distribution

Leon

Hi Leon

I am new to this subject.I would like you to refer six sigma for quality and productivity promotion-sung H.PARK.

True value is only desired but process mean during one time period is not same with other time due to unavoidable reason.due to this in 6 sigma level process defect is correspond to 3.4 PPM in place of zero.

I may be wrong but 6 sigma levle is +/-6 sigma ipo of +/-3sigma.Plz correct me any body if my concept is not wrong.

Anil gupta

Hi Anil,

Thanks f or sharing. Yes, 6 sigma level is +/- 6 sigma instead of +/-3 sigma because of 1.5 sigma shift. But my key question is what is the justifiable rationale of such shift and make it +/- 6 sigma instead of +/- 3 sigma prior to Motorola concept of 1.5 sigma shift.

Thanks

Hi, 

 

This topic has been discussed at http://forum.benchmarksixsigma.com/topic/771-what-is-15-sigma-shift/