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Capability Indices calculation for Nonnormal Distributions in Percentile Methods

Hi, I would like to figure out how JMP 16 Calculate Ppk in non-parametric method. So I calculate Ppk in R code with the formula in online documentations, but the results are very different. Could anyone help me to understand if it is my calculation error or the documentation?

 

Quality and Process EngineeringRe: Capability Indices calculation for Nonnormal Distributions in Percentile Methods

Hi Wang,

 

Sorry for reply so late, I calculate the P0.99865 and P0.00135, the result from JMP and R are still very close.

 

 

Re: Capability Indices calculation for Nonnormal Distributions in Percentile Methods

Hi Luna

考虑到基础统计量计算结果的不同导致最终结果的不同。不知道是否方便讲JMP中基础统计模块的0.99865/0.00135的结果显示一下。方便和R做对比。

具体的方法可在红色三角形中选择option-->客户定制。

Re: Capability Indices calculation for Nonnormal Distributions in Percentile Methods

For those having trouble following the conversation...

 

Hello, I simply used R to calculate some percentiles, which are slightly different from JMP, but the Ppk calculation result is too different (R:2.026, JMP: 1.678), which may not be the error caused by the percentile calculation method .

Re: Capability Indices calculation for Nonnormal Distributions in Percentile Methods

For those having trouble following the conversation...

 

Are there any results for basic statistics? See if the results of the quantiles are consistent. If the formula itself is not a problem.

Re: Capability Indices calculation for Nonnormal Distributions in Percentile Methods

你好，我简单用R计算了一部分百分位数，和JMP略有差异，但Ppk计算结果差别太大了（R:2.026, JMP: 1.678），可能不是百分位数计算方法造成的误差.

 

Re: Capability Indices calculation for Nonnormal Distributions in Percentile Methods

Hi Luna

JMP基础统计的结果有吗？看看分位数的结果是否一致。如果公式本身没有问题的情况下。

Re: Capability Indices calculation for Nonnormal Distributions in Percentile Methods

Sorry I post wrong JMP results, the JMP results are as follow: