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Josh1
Level II

Measurement System Analysis Bias Comparison vs ANOM decision limits

I'm curious why the decision limits for the Bias comparison ANOM in the MSA tool are narrower than those generated by fit Y by X.

 

From MSA

 

Josh1_0-1665507988327.png

Same data but from the Y/X tool:

Josh1_1-1665508019133.png

The Y/X limits are 2X wider than the MSA limits.

 

Both charts are using a sample size of 30.   

Josh1_2-1665508041008.png

I believe these are the ANOM decision limit equations since they are referenced in JMP help

Josh1_3-1665508063288.png

Alpha level, subgroup size, and within subgroup sample sizes are the same for both charts. 

Why would the decision limits be 2X larger on the fit Y by X generated ANOM chart?

1 REPLY 1

Re: Measurement System Analysis Bias Comparison vs ANOM decision limits

Hi @Josh1 ,

 

I think this might be one for support@jmp.com. IF they are using the same formulas, then something else is causing a ~0.00494 difference to the upper and lower decision limits.

Chris Kirchberg, M.S.2
Data Scientist, Life Sciences - Global Technical Enablement
JMP Statistical Discovery, LLC. - Denver, CO
Tel: +1-919-531-9927 ▪ Mobile: +1-303-378-7419 ▪ E-mail: chris.kirchberg@jmp.com
www.jmp.com