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#### dzarr

Hi,

I have just been introduced to MSA and I have a couple of questions.

I have been studying on ways how to mount accelerometers onto human skin in order to measure skin accelerations (vibration). I was not happy with the result as the acceleration amplitude tends to fluctuate during repeated measures.

As I was searching for a way to analyze measurement capability, I stumbled upon AIAG MSA 4th Ed. After having improved the method and the repeatability on a single operator I have moved on to the factorial analysis using the recommended 10 parts, 3 operator and 3 replicates.

I have repeated my test and increased appraisers number from 3 to 6 to narrow down the confidence interval for %StudVar and ndc. I have since moved away from %StudVar to %Contribution which I think is the more appropriate metric in my situation. I should say I am happy with the outcome, the upper limit of gage r&r 95% CI is below 9. Attached herein is the minitab two-way ANOVA gage study result with 95% CI.

As I have had no formal training on Gage Analysis (mostly reading) I am concern that I might have got to a wrong footing.

My questions;

1. Is it statistically correct to make the following conclusion from the analysis data.

The measurement error contributes only 2.92% from the total measurement variance. As the upper limit at 95% CI is 6.51% which is less than 9%, this is an acceptable method for measuring.....

2. I wanted to cite the reference for the %contribution. GRR<1, 1>=GRR<=9, GRR>9. AIAG only provided the guidelines on %StudVar and ndc. Who first recommended the limits for %contribution? one which I could cite.

Thanks

A.Dzarr

I have just been introduced to MSA and I have a couple of questions.

I have been studying on ways how to mount accelerometers onto human skin in order to measure skin accelerations (vibration). I was not happy with the result as the acceleration amplitude tends to fluctuate during repeated measures.

As I was searching for a way to analyze measurement capability, I stumbled upon AIAG MSA 4th Ed. After having improved the method and the repeatability on a single operator I have moved on to the factorial analysis using the recommended 10 parts, 3 operator and 3 replicates.

I have repeated my test and increased appraisers number from 3 to 6 to narrow down the confidence interval for %StudVar and ndc. I have since moved away from %StudVar to %Contribution which I think is the more appropriate metric in my situation. I should say I am happy with the outcome, the upper limit of gage r&r 95% CI is below 9. Attached herein is the minitab two-way ANOVA gage study result with 95% CI.

As I have had no formal training on Gage Analysis (mostly reading) I am concern that I might have got to a wrong footing.

My questions;

1. Is it statistically correct to make the following conclusion from the analysis data.

The measurement error contributes only 2.92% from the total measurement variance. As the upper limit at 95% CI is 6.51% which is less than 9%, this is an acceptable method for measuring.....

2. I wanted to cite the reference for the %contribution. GRR<1, 1>=GRR<=9, GRR>9. AIAG only provided the guidelines on %StudVar and ndc. Who first recommended the limits for %contribution? one which I could cite.

Thanks

A.Dzarr