Cpk DAX

[vincentakatoh]

Hi, 

Need help to write DAX to calculate Cpk

Cpk formula

Sample data

 

current dax

Xbar = AVERAGE(Table[MeasureValue])
STDEV = STDEV.S(TableMeasureValue])

Abbreviations

USL= Limit Upper

LSL= Limit Lower

STDEV= sigma

[Greg_Deckler · Accepted solution]

Not entirely sure how you are using this, but perhaps something like:

Cpk = 
VAR CpU = (MAX([LimitUpper]) - [Xbar])/3*[STDEV]
VAR CpL = ([Xbar] - MAX([LimitLower]))/3*[STDEV]
RETURN MIN(CpU,CpL)

[vincentakatoh]

@Greg_Deckler, 

Awesome and thanks alot. 

PS. added a "( )" for ( 3*[STDEV] )

Cpk = 
VAR CpU = (MAX([LimitUpper]) - [Xbar])/(3*[STDEV])
VAR CpL = ([Xbar] - MAX([LimitLower]))/(3*[STDEV])
RETURN MIN(CpU;CpL)

[Greg_Deckler]

@vincentakatoh- I created a Quick Measure page for these kinds of process measures if you need any others or if you want to check that I didn't make any other mistakes!

https://community.powerbi.com/t5/Quick-Measures-Gallery/Process-Improvement-Measures-Cp-Cplower-Cpup...

[Greg_Deckler]

Yeah, I actually added those too after my post I was looking at the formulas and thinking, hmmm...I think it needs some parens... 🙂