Count by weight statistical analysis

Elsmar Forum Sponsor

Statistical Steven

Statistician
Staff member
Super Moderator
#12
OK - lets give this a shot.... using an online tool (as I have zero experience of my own with this :eek:) I came up with the following table... could someone who understands this better than I please tell me if its anywhere near accurate? THANKS!
Looks like you used a power of 85%, is this true? In general, it looks right, but this is not the question you wanted answered. You are not taking a sample from the lot and weighing it to ensure the correct weight.
 

smryan

Perspective.
#13
Looks like you used a power of 85%, is this true? In general, it looks right, but this is not the question you wanted answered. You are not taking a sample from the lot and weighing it to ensure the correct weight.
No idea about the power of 85% - pic of tool used attached.

Correct, the weight is not the goal, an accurate count is. But the weight is what is used to determine the count, so if the weight is accurate then the count should be too.... right?:confused:
 

Attachments

Miner

Forum Moderator
Staff member
Admin
#14
No idea about the power of 85% - pic of tool used attached.

Correct, the weight is not the goal, an accurate count is. But the weight is what is used to determine the count, so if the weight is accurate then the count should be too.... right?:confused:
This calculator is specific to surveys. This is not appropriate for your situation.
 

smryan

Perspective.
#15
This calculator is specific to surveys. This is not appropriate for your situation.
:notme:I was hoping that wouldn't matter. When I say I have no statistical background I mean it very literally. Can someone help me find the approprite tool? I don't even know how to narrow down my search.:(

I use software like SAS, though you can do it in Excel too. You will need to actually do the simulation twice...
I'd like to try - I use Excel - but how? Or is this way beyond the scope of the forums?
 
D

Denis

#16
You have quite a bit of variation in the recorded weights.

Would it be possible to work with the supplier of these parts to reduce and understand the causes of the weight variation? I would look at trying to work with the supplier in the first instance.

Are they aware of the critical nature (to you) in this process?

Once you understand the root cause of the variation it might be easier to work on some solutions to eradicate the variation (never completely, but at least improve it).

Then repeat the study, or get the supplier to put some in process checks in place to detect the weight changes etc.
 

Miner

Forum Moderator
Staff member
Admin
#17
:notme:I was hoping that wouldn't matter. When I say I have no statistical background I mean it very literally. Can someone help me find the approprite tool? I don't even know how to narrow down my search.:(


I'd like to try - I use Excel - but how? Or is this way beyond the scope of the forums?
Can you attach any actual, not summarized data for us to work with?
 

smryan

Perspective.
#18
OK - attached is the data I am currently working with. "Results" tab - the yellow & blue section I am pretty sure of. The green section is what I am unsure of. Which (if any) of the 3 would be the most true? (and why?):rolleyes:

The "data" tab has the masses of the 8 bags of 50 pieces. And the 150 pieces I had time to mass before they were shipped.

The parts are all within spec, so telling the sub to "make them better" would be poorly received. :whip: BUT the variance should be considerably less per run (it is here, anyway). So my one thought is to have the sub bag the pieces from each run separately instead of 30,000 or so pieces loose in the box. It would add a small step on both ends, but it could increase accuracy in shipping quantities.

So.... suppose the part variance becomes a much smaller issue. Given the possible non-normal distribution (based on this data) of what variance there still would be, can one statistically speculate that "A sample size ____% of the total count will give you ___% accuracy in your count"?
 

Attachments

Last edited:

Miner

Forum Moderator
Staff member
Admin
#19
I looked at your data. Did you notice that the individual samples as well as the combined data set are bimodal? Furthermore, the two modes are the same on all three samples.

If you can resolve this, it would reduce your total variation significantly and reduce your count problem.
 

smryan

Perspective.
#20
I looked at your data. Did you notice that the individual samples as well as the combined data set are bimodal? Furthermore, the two modes are the same on all three samples.

If you can resolve this, it would reduce your total variation significantly and reduce your count problem.
We need a smiley with a lightbulb going off =) :thanks:
No, I hand't noticed the bimodality in the data. My thought is the separate bagging of parts from each "run" would eliminate this - but if it doesn't is there another way to look at it?
 
Thread starter Similar threads Forum Replies Date
G Count By Weight Scale - Calibration within specification, but not linear General Measurement Device and Calibration Topics 8
P ISO Class 8 particle count (annual certification vs monitoring) ISO 13485:2016 - Medical Device Quality Management Systems 4
A AQL - How to count samples with defects for each defect class AQL - Acceptable Quality Level 17
M Viable count Measurement ISO Standard Other Medical Device Related Standards 1
supadrai How does the FDA count violations of, for example, misbranding? (Medical Devices) Other US Medical Device Regulations 1
M How to count the number of employees? Other Medical Device and Orthopedic Related Topics 4
M ISO 14644 Airborne Particle Count Testing Requirements Miscellaneous Environmental Standards and EMS Related Discussions 6
A Difference between Discrimination and Least Count IATF 16949 - Automotive Quality Systems Standard 2
W Legality of selling parts by count - Counting Scales Quality Manager and Management Related Issues 6
C Do Emails count as a Document/Record Document Control Systems, Procedures, Forms and Templates 6
S Head Count for Employees and Contract Workers Misc. Quality Assurance and Business Systems Related Topics 6
C What is an acceptable bioburden level or count when working in cleanroom ISO class7 ISO 13485:2016 - Medical Device Quality Management Systems 1
R Count NDC from Graphik Sample Range vs R chart Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
F Excel I want to use the count I get in another formula Excel .xls Spreadsheet Templates and Tools 13
N Requirements for the Classification of Cleanrooms other than the Particle Count Other ISO and International Standards and European Regulations 5
D Pls hlep me understand the "Total Anaerobic Plate Count" Food Safety - ISO 22000, HACCP (21 CFR 120) 1
T Significance Test for Count Data Statistical Analysis Tools, Techniques and SPC 8
M Setting Solid Dose Drug Fill Count Ranges Pharmaceuticals (21 CFR Part 210, 21 CFR Part 211 and related Regulations) 8
S Do Medical Sterile Drapes count as MOPP? IEC 60601 - Medical Electrical Equipment Safety Standards Series 2
I Bioburden Count Question - Bioburden is above the alert limit >1 CFU/component avg. 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 1
L GB15980-2003 Bioburden Count Trend on Operator Hands Other ISO and International Standards and European Regulations 1
S Count (Bolts and Nuts) Scale - Class of Calibration Weights Calibration and Metrology Software and Hardware 3
K Preventing Shortage of Product Quantity - Hand Count and Scale Count Manufacturing and Related Processes 13
D 510K Approval Guidelines and Marketing in the US - CD4 Count Reagent 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 1
R While Measuring Filter Face, Why We Count From Dead Area? HEPA Filter Related Manufacturing and Related Processes 3
Y Environmental Monitoring - Setting for Particulate Count ISO 13485:2016 - Medical Device Quality Management Systems 3
L Labeling and Count/Part Reconciliation Manufacturing and Related Processes 8
B Does this count as a 510(k) Medical Device Modification 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 14
M Devices with Measuring Function - Do rulers and calipers count? EU Medical Device Regulations 7
B Minitab Gage R&R using Defect Count per Unit Area Using Minitab Software 1
L Do "Informal" Internal Audits count? Internal Auditing 18
S How to count the number of NCs in an Internal Audit? General Auditing Discussions 18
C Do Newsletter articles count towards recertification? Professional Certifications and Degrees 1
T Does a years worth of prototype manufacturing "count" for TS 16949? IATF 16949 - Automotive Quality Systems Standard 6
A Class 8 100,00 Cleanroom - Airborne Microbial Count ISO 13485:2016 - Medical Device Quality Management Systems 6
Q Latest count of ISO 9001 Registration Certificates world wide ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 22
S The Logic behind Tolerance vs. Least Count 1/10 Ratio General Measurement Device and Calibration Topics 11
N Auditing Inventory Levels - Computer Count vs. Physical Inventory ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 40
B R&R Study in Microbiological Testing - Aerobic Plate Count, Coliform, and Salmonella Food Safety - ISO 22000, HACCP (21 CFR 120) 4
Jim Wynne Vista Deathwatch - Is the new Microsoft OS down for the count? World News 30
Jen Kirley How to count two criteria at once in Excel Excel .xls Spreadsheet Templates and Tools 17
Manix MTTF Prediction for Customer Requirements - Parts-count MTTF prediction for the part Reliability Analysis - Predictions, Testing and Standards 2
V Minitab Pareto - Trying to plot a relation of Count and Cycle Time Using Minitab Software 5
J Cumulative Count of Conforming Control Chart (CCC) - Calculating UCL and LCL Statistical Analysis Tools, Techniques and SPC 8
S Attribute GRR - Cross tab - Kappa - What does "Expected Count" mean? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
M Can multiple procedures count as one? Different aspects of document control system Document Control Systems, Procedures, Forms and Templates 6
T 3rd party audit time - Does working lunch count as audit time? General Auditing Discussions 66
Wes Bucey At the end of the day, only votes count! World News 5
D Gage R&R on a delta measurement - Particle measurement count tool Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
C Least count thumb rule - Stone walling SPC Statistical Analysis Tools, Techniques and SPC 7

Similar threads

Top Bottom