# AIAG's MSA Reference Manual, page 95, "Gage R&R Confidence Intervals"

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#### Ben

Reference AIAG's MSA Reference Manual, page 95, "Confidence Intervals"

Does anyone know of a supplemental text I can go to in order to figure out how to determine confidence intervals for a gage R&R study?

I apologize, but I cannot interpret the phrase "where MS denotes percentage point for a mean square distribution (i.e., a Chi-square deviate with the same degree of freedom divided by degrees of freedom, v)"

Thank you.

#### Marc

##### Hunkered Down for the Duration
Staff member
Any statistical gurus out there with a comment or 2 on this?

M

#### max

The formulas might be in some SPC texts. Here is a journal reference:

"Gauge Capability Analysis and Designed Experiments. Part II: Experimental Design Models and Variance Component Estimation" by Montgomery and Runger, Quality Engineering, Vol. 6, No. 2, OCTOBER 1993, pp. 289-305.

(part I: Quality Engineering, Vol. 6, No. 1, JULY 1993, pp. 115-135)

As for "where MS denotes percentage point for a mean square distribution (i.e., a Chi-square deviate with the same degree of freedom divided by degrees of freedom, v)": if you use ANOVA to get your results from the study, there will be mean squares for part, operator and so on. Each mean square has a specific degree of freedom associated with it. These numbers (the df) are needed to compute the confidence interval.

For example, we performed an R&R study with 16 parts. There are 16-1=15 degrees of freedom for the part source of variation in the study. If I wanted to get the 5th percentage point for a Chi-square distribution with 15 df, Excel would give it to me with CHIINV(0.05,15), which is 24.99.

Consult the references above. They are written for non-statisticians.

A Product or Process Tolerence - AIAG MSA Reference Manual 3rd edition page 3 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
The FILE recommended by AIAG MSA 4ed for LINEARITY Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
AIAG's IATF 16949 section 7.1.5.1.1 - Torque MSA Requirement Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
ANOVA GR&R: Minitab vs AIAG MSA results Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
C PPAP Rejection for "MSA-GR&R are not using the latest AIAG format" APQP and PPAP 9
V Latest revisions of Core Tools Manuals from the AIAG (APQP, PPAP, FMEA, SPC and MSA) IATF 16949 - Automotive Quality Systems Standard 3
Definition Equipment definition - What does "equipment" mean in the AIAG MSA Manual Definitions, Acronyms, Abbreviations and Interpretations Listed Alphabetically 1
H Is my MSA Study Spreadsheet okay to AIAG MSA Manual 4th Edition? Using Minitab Software 18
Q Using Traceable Standards - AIAG MSA Manual Chapter II, Section B, 1st bullet Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
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S AIAG MSA 4th Edition Summary APQP and PPAP 4
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J Where to buy AIAG MSA 3rd Edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
T When is GRR (Gage R&R) required? AIAG MSA Manual Version 4 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 19
AIAG MSA (Measurement Systems Analysis) Manual 3rd ed. Chapter IV Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
O Problems calculating the observed CP - Page 19, AIAG MSA manual 3rd edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
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S Are the AIAG document (FMEA, PPAP, SPC, MSA, APQP) guidelines or requirements FMEA and Control Plans 6
P AIAG SPC Manual (ver.1) Interpretations related to Gage R&R (GR&R) and MSA IATF 16949 - Automotive Quality Systems Standard 8
C AIAG Attribute MSA - Analytical Method - Page 135 of MSA manual 3rd edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 19
A Significance of X chart in AIAG MSA sheet for Gage R&R Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
AIAG SPC and MSA guidelines - Which are the latest revisions? Statistical Analysis Tools, Techniques and SPC 3
K Need a version of the AIAG's MSA (Measurement System Anaysis) 3rd Edition Checklist Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
T MSA using tolerances - Page 116 of the AIAG MSA manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 30
S Bias Study Confidence Intervals - Page 88 of the AIAG MSA manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 11
Errata for the AIAG's MSA Third Edition; 1st and 2nd printings Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
D What the AIAG manual says about the frequency of MSA - Measurement system analysis Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 11
P Has K1 for GR&R's changed in AIAG 3rd ed MSA Manual? Does it affect outcome of study? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
T TS 16949 - AIAG's MSA Manual - Thread Inspection Gage - Attribute Gage R&R Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
G Bias & Linearity Calculations and T Value Formula in the AIAG's MSA Manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
S Number of Distinct Data Categories - NDC - AIAG's MSA Manual 3rd edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
D Linearity Analysis - AIAG's MSA Manual 3rd Edition - Question Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
D Linearity Analysis - Measurement System Analysis - AIAG MSA Manual 3rd Edition Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 14
J AIAG's MSA Manual 3rd Edition Attribute Gage Study - Calculating the UCI and LCI Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
Y AIAG's MSA (Measurement Systems Analysis) 3rd Edition - K1, K2, K3 constants Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
V AIAG's MSA III Edition - Forms and Formulas - Attribute Gage R&R Document Control Systems, Procedures, Forms and Templates 3
M Attribute Gage R&R Form - Long Version - AIAG's MSA Manual Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 35
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J AIAG MSA and Gage R&R - What does the Process Variation % R&R truly mean? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 11
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