📋 Workflow
Full workflow, products add-to-cart directly1
Measurement model
2 hDefine the mathematical model of measurement and all input quantities
💡 Tip List all influencing quantities
⚠️ Caution Correctly distinguish input vs output quantities
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2
Identify uncertainty sources
3 hList sources such as standards, weighing, dilution and instrumentation using an Ishikawa diagram
💡 Tip Be comprehensive without omissions
⚠️ Caution Avoid double counting
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3
Type A evaluation
4 hCompute standard uncertainty statistically from repeated measurements
💡 Tip Use standard deviation of replicates
⚠️ Caution Adequate sample size
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4
Type B & combination
4 hEvaluate Type B components from distributions (standards/instruments) and combine
💡 Tip Assign distributions per certificate/manual
⚠️ Caution Choose the coverage factor correctly
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5
Expanded uncertainty & report
3 hMultiply by coverage factor k to obtain expanded uncertainty and append to result
💡 Tip Often k=2 (95%)
⚠️ Caution Report the coverage factor
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⚠️ 5 Common Beginner Mistakes
- ① Missing uncertainty sources
- ② Confusing Type A and Type B evaluations
- ③ Wrong coverage factor
- ④ Double counting or missing components
- ⑤ Report omits uncertainty
❓ FAQ
+Type A vs Type B?
Type A uses statistics; Type B uses distributions/expertise.
+Why k=2?
Covers about 95% confidence; widely adopted.
+Is bigger uncertainty better?
No; it should genuinely reflect measurement reliability.