Linearity Study - Tolerance for which Ref Value

Rameshwar25

Quite Involved in Discussions
#1
In linearity study, there is one requirement to calculate %EV based on either on tolerance or process standard deviation. The linearity study is conducted for more than one ref values (usually 5). My question is that for the purpose of %EV calculation, tolerance/ standard deviation for which ref. value should be used because each ref. value may have different tolerance and definitely different standard deviation?

Regards
Rameshwar
 
Elsmar Forum Sponsor

Stijloor

Staff member
Super Moderator
#2
In linearity study, there is one requirement to calculate %EV based on either on tolerance or process standard deviation. The linearity study is conducted for more than one ref values (usually 5). My question is that for the purpose of %EV calculation, tolerance/ standard deviation for which ref. value should be used because each ref. value may have different tolerance and definitely different standard deviation?

Regards
Rameshwar
Can our MSA Experts help Rameshwar?

Thank you!!

Stijloor.
 

Rameshwar25

Quite Involved in Discussions
#3
I further elaborate my query:
Suppose that study is condusted on 5 ref values i.e. 2,4,6,8 and 10. The tolerances for these ref values are ±0.02, ±0.04, ±0.06, ±0.08, ±0.10 respectively. in 12 trials, total 60 observations are taken and the std dev of these 60 observations is .2395. For the purpose of %EV calculation, which tolerance of above 5 should be used?

Regards
Rameshwar
 

Statistical Steven

Statistician
Staff member
Super Moderator
#5
I do not know the MSA guidelines specifically, but %EV is the percent of the the Gage R&R attributed to repeatability. Just use the square root of the MSE from the regression model to estimate the repeatability.
 

Rameshwar25

Quite Involved in Discussions
#6
Is this an academic question, or do you have actual data?
The data are from MSA manual (4th Ed), Linearity example, Pg 99. I have just added tolerances in my question. the page is attached herewith.

Also the page containing formula for calculating %EV is attached (Pg 97 of MSA Manual).

regards
Rameshwar
 

Attachments

Last edited:
B

Barbara B

#7
Maybe for different tolerance width instead of the values the deviation from the reference value in percent (0%=reference value, -100%=LSL, +100%=USL) could be used.

Regards,

Barbara
 
B

Barbara B

#8
To elaborate this idea a little bit further:

Subtract the reference value from a measurement and divide the result by 0.5*tolerance width. E.g. for a reference value of 8.0 with ±0.10 tolerance (so 0.5*tolerance width=0.10) and measured values of (7.95,8.0, 8.05, 8.1, 8.2):

value-reference = (-0.05, 0.00, 0.05, 0.10, 0.20)

(value - reference) / 0.5*tolerance width
= (-0.05, 0.00, 0.05, 0.10, 0.20) / 0.10
= (-0.50, 0.00, 0.50, 1.00, 2.00)
= (-50%, 0%, 50%, 100%, 200%)

Best regards,

Barbara
 

Rameshwar25

Quite Involved in Discussions
#9
Thank you Barbara for explanation
Your calculation has given 5 different readings for different ref. values while we need to calculate %EV as a single numerical value fir the study.
My opinion is to first take average of all five tolerance values and use this average as TV.
Example 1 (MSA Manual data)
Average=(.04+.08+.12+.16+.2)/5=.12
%EV=StdDev from study data*100/(Tol/6)=.2395*100/(.02)=1197.5%

Although this much percentage seem to be alarming, it seems to be realistic for the data given in MSA manual where repeated observations vary from 2.4 to 2.7 for a ref value of 2.00.
Example 2:
stddev=.0137, Ref Values: 8.52±0.04, 16.86±0.05, 22.9±0.06, 47.16±0.08, 56.1±0.08
%EV =.0137*100/(.124/6)=66.29%


Regards
Rameshwar
 
Last edited:
Thread starter Similar threads Forum Replies Date
W Using MPE (Mean Percentage Error) for Linearity and Type-1 study Measurement Uncertainty (MU) 1
B Linearity study on a non-linear gage General Measurement Device and Calibration Topics 7
P Purpose of calculating Ta, Tb & R Square in Linearity Study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
P The correct way to do a Linearity and Stability Study on a Critical Dimension Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
G Bias & Linearity Study and the Uncertainty of Standards Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
I Interpretation of MSA (Measurement Systems Analysis) Linearity and Bias Study Results Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
T Bias & Linearity Study - How to calculate the P value for the Average Bias Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
C Linearity and Bias Study Compliance Requirements Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
L Gage Linearity and Bias Study Analysis - Minitab help needed Using Minitab Software 4
Rameshwar25 Trendline-Linearity - Questions related to Linearity study graph Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
C "Destructive" Linearity Study Methodology Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
F R-sq index in Linearity study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
L Recommend a 3rd Party Certifier for Master Value in Linearity & Bias Study General Measurement Device and Calibration Topics 0
B In a Linearity Study covering the operating range is it necessary to do Bias Study? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
I R-sq Value is Almost Zero - Linearity Study Question Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
B Any Easy Way to determine Linearity Study Acceptability? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
A Linearity and Bias Study - Bias Study fails - Seeking advice Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
A Do we need to perform Stability, Linearity & Bias study for Attribute data? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
A Is minitab 'AIAG compliant' to perform GR&R, linearity and bias study? Using Minitab Software 4
S Linearity study - What is required to draw graph and make decison based on the graph Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
D Gagetrak software: 6 sigma process variation reqd for Linearity Study? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
B What are the Acceptance Criteria for Linearity Study? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
L MSA Manual Example of a Linearity Study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
M Test method validation - Is MSA (MSA1, MSA2, MSA3 and linearity) a good solution? Medical Device and FDA Regulations and Standards News 1
A Acceptance p-value for linearity and bias analysis in minitab results Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
A The FILE recommended by AIAG MSA 4ed for LINEARITY Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
M How calculate P value for Linearity and Bias using Excel Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
E Company-wide MSA - Measurement Equipment Bias, Linearity & Stability Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
M Are Bias, Stability, and Linearity studies required by TS 16949 7.6.1? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
E Gage Linearity and Bias Questions Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
E How to Properly Apply Linearity - How does it "Fit"? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
I Difficulty with calculated t-value for Linearity Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
A Bias Linearity Stability MSA Excel File with Formula Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
M Profilometer Patch - Gain does not match, Linearity and Stylus = Good General Measurement Device and Calibration Topics 4
V Excel Linearity Chart - drawing 95% CI line & set X-axis at the bottom Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 13
Rameshwar25 Linearity Problem (MSA - Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
T Gage Bias and Linearity - How to interpret the Minitab results Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
Rameshwar25 MSA Manual 4th Edition, Page 100 - What is wrong in the Linearity graph? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
S MSA 4th Edition formats in Excel wanted - GR&R, Bias, Stability and Linearity Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
J Uncertainty Budget for the Optical Microscope - Deriving Linearity Uncertainty Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
S Linearity Calculation Worksheet (including formula) General Measurement Device and Calibration Topics 1
M Linearity, BIAS & Stability - How many studies do I need to do for a device? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
Miner Intro to Measurement System Analysis (MSA) of Continuous Data – Part 3: Linearity Imported Legacy Blogs 15
B Can any one help me in Linearity calculations & acceptance criteria Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
S Stability, Bias and Linearity samples - Measurement Systems Analysis Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
F Linearity Analysis - MSA 3rd edition, March 2002 page 93 formulas Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
M When to use Linearity and Bias - appropriate for paper tensile strength? Quality Tools, Improvement and Analysis 6
A Linearity and Eccentricity Point Definitions - Ref: ISO/IEC 17025:2005 ISO 17025 related Discussions 1
S If I do Linearity and Bias Studies, are Stability Studies Required? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
Ron Rompen MSA to perform Linearity and Stability studies on Variable Gauges with Minitab Ver 15 Using Minitab Software 6

Similar threads

Top Bottom