把DPMO/SIGMA换算成CPK

Cpk = Z短期除以三

如果是以DPMO计算,就把数值除以1百万,在Z表格中找出该数据对应的Z数值,MINITAB就是根据这个原理计算的,但是算出的是长效Z,Z短期值的计算是把Z长效值+1.5

However, if you are starting with DPMO, convert it to a decimal value(divide by 1,000,000), look this decimal value up in a standard normal curve(z table) and find the corresponding z. Minitab can do this as well. Anyway this is long term z. To convert to short term z which is sigma level:

z(short term) which is sigma level = Z(long term) + 1.5

then you can plug into the equation above to get Cpk