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sangram
Community Member

How to interpret the result of random effects model in JMP?

I fitted a random effects model with 2 factors (Part No. and Operator) by selecting the "Random Effects" option under "Attributes" on "Fit Model" window (with interaction Part*Operator).

I received the following output under REML Variance Components Estimates table.

 

Random Effect

Var Ratio

Var Component

Std Error

95% Lower

95% Upper

Wald p-Value

Pct of Total

Part

1.1555556

1.7333333

0.8656795

0.0366326

3.430034

0.0453*

53.608

Operator

-0.004115

-0.006173

0.0218

-0.0489

0.0365544

0.7771

0.000

Part*Operator

-0.199588

-0.299383

0.1464372

-0.586394

-0.012371

0.0409*

0.000

Residual

 

1.5

0.3354102

1.0110933

2.4556912

 

46.392

Total

 

3.2333333

0.9283863

1.9759148

6.2317667

 

100.000

 

  -2 LogLikelihood = 203.88510393

 

How to interpret these results?

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2 REPLIES 2
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Re: How to interpret the result of random effects model in JMP?

The main result of REML is the Var Component column. The components from the model sum to the Total. The next result is the confidence interval or p-Value for the Wald ratio. The Part and Part*Operator estimates appear to be significantly different from zero. Model hierarchy requires keeping the Operator term even though it does not appear to be different from zero.

 

The negative estimate for the interaction component is because it is really a covariance, which can be negative. Another community member might have more insight in the interpretation in the case of MSA.

 

The Part variance is about 54% of the total and the residual (repeatability) is about 46% of the total, so this measurement system is not good.

 

Did you also analyze your data with the Variability Chart platform?

Learn it once, use it forever!
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P_Bartell
Contributor

Re: How to interpret the result of random effects model in JMP?

I'll add just a bit to @markbailey 's explanation by making sure that you ALSO plotted the data using a variety of the graphical techniques available in the Gauge R & R and/or Measurement Systems Analysis platforms and subplatforms. These charts can often times be very informative by visualizing features/characteristics in the measurement system that are of interest and valuable over and above the static tabular results that are also presented. Here's a link to the online documentation for the MSA platform as a good place to start:

 

https://www.jmp.com/support/help/14-2/measurement-systems-analysis.shtml#

 

And here's a JMP On Demand Mastering JMP webinar that I hosted during my SAS tenure that you might also find valuable:

 

https://www.jmp.com/en_us/events/ondemand/mastering-jmp/evaluating-and-monitoring-your-process-using...

 

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