你看过这样算cpk吗？请高手指点。

原样拷贝计算过程。拿到的资料是英文的。
1。 pwi
For instance, set the upper and lower limit of temperature as 225 and 205 °C respectively,if the actual temperature is 223 °C, then refer to the picture.


2。 CPK
CpK = (|Mean|)/3s

Mean = Mean of the data points
s = Standard deviation of the data points calculated for a whole population

s= Square root of

N = Number of items in a population, process, or lot.
X = Set or group of data, observations, or measurements
In the calculation of CpK on PWI values, the Upper Spec Limit is always “100” and the lower spec limit is always “ -100”. If we take the absolute value of the mean then we can always use 100 as the spec limit.

Here’s is a simple example. Let’s set the Points to Compute Cpk is set to 5, and the 5 PWI values are as follows: 68%, 83%, 70%, 64%, and 50%.

Mean= (68 + 83 + 70 + 64 + 55) / 5 = 68

StdDev = Square Root
= Square Root
= Square Root
= 9.10

Cpk = (100 - |68| ) / (3 • 9.10)
Cpk = 32 / 27.31
Cpk = 1.17