Accuracy

Relationship

Accuracyisthedifferencebetweentheaveragevalueofeachindependentmeasurementandthetruevalueoftheknowndata(thedegreeofconformitywiththetheoreticalvalue).Forexample:theaveragevalueoftheresultsofmultipleexperimentsisclosetotheknowntruevalueofthedata(theoreticalvalue),itcanbeknownthatthedatais"accurate"orthedatahas"highaccuracy";conversely,theaveragevalueisthetruevalueoftheknowndataAlargegapindicatesthattheexperimentaldataisinaccurateortheaccuracyisnothigh.

Precisionmeansthatwhentheexperimentaldataisveryaccurate,theexperimentisrequiredtohaveahighdegreeofreproducibility,indicatingthattheexperimentaldataiscredible,thatis,theexperimentaldataneedstohavehighprecision(multiplemeasurementsorcalculations)Thedegreeofagreementoftheresults).

Highmeasurementaccuracymeansthatthesystemerrorissmall.Atthistime,theaveragevalueofthemeasureddatadeviateslessfromthetruevalue,butthedataisscattered,thatis,thesizeoftheaccidentalerrorisnotclear.

Highmeasurementprecision(alsooftenreferredtoasprecision)meansthataccidentalerrorsarerelativelysmall,andthemeasurementdataisrelativelyconcentratedatthistime.

Althoughhighprecisionindicatesthattheexperimentisreproducible,itsresultsmayalsobeinaccurate.Similarly,highaccuracyindicatesthatthetestresultisclosertothetruevalue,butitsreproducibilitymaynotbegood.

Forexample,whena1mg/Lstandardsolutionisusedformeasurement,theresultsobtainedbyAare0.95mg/L,0.99mg/Land1.03mg/L,respectively,andtheresultsmeasuredbyBare1.73mgrespectively/L,1.74mg/Land1.75mg/L.TheresultofAisclosertothetruevalue,andtheaccuracyishigh,buttheprecisionislessthanthelatter.WhileB'smeasurementhashighprecisionandgoodreproducibility,butitsaccuracyislowerthantheformer.

Definition

1.Precision

Theprecisionofmeasurement(precisionofmeasurement)referstothedegreeofagreement(coincidence)betweenthemeasuredvalues​​afterrepeatedmeasurementsunderthesameconditions.Fromtheperspectiveofmeasurementerror,precisionreflectstherandomerrorofthemeasuredvalue.Highprecision,notnecessarilyhighaccuracy(seebelow).Inotherwords,therandomerrorofthemeasuredvalueissmall,andthesystematicerrorisnotnecessarilysmall.

2.Accuracy

Theaccuracyofmeasurementreferstotheclosenessofthemeasuredvaluetoits"truevalue".Fromtheperspectiveofmeasurementerror,accuracyreflectsthesystematicerrorofthemeasuredvalue.Highaccuracyisnotnecessarilyhighprecision.Inotherwords,thesystematicerrorofthemeasuredvalueissmall,notnecessarilyitsrandomerrorisalsosmall.

3.Accuracy

Theaccuracyofmeasurement,alsoknownasaccuracyofmeasurement,referstothedegreeofagreementbetweenthemeasuredvalues​​andtheclosenesstothe"truevalue".Itisacomprehensiveconceptofprecisionandaccuracy.Fromtheperspectiveofmeasurementerror,accuracy(accuracy)isacomprehensivereflectionofrandomandsystematicerrorsofthemeasuredvalue.

Inengineeringapplications,inordertosimplyexpressthereliabilityofthemeasurementresults,theconceptofaccuracylevelisintroduced,whichisrepresentedbyA.Theaccuracylevelisdividedintoaseriesofstandardpercentagevalues​​(0.001,0.005,0.02,0.05,...,1.5,2.5,4.0).Thisvalueisthepercentageofthemaximumallowableabsoluteerrorofthemeasuringinstrumentrelativetoitsmeasuringrangeunderspecifiedconditions.Itcanbeexpressedbythefollowingformula:A=△A/Y×100%(whereArepresentsaccuracy,△Arepresentsthemaximumabsoluteerrorallowedbyitsmeasuringrange,andYrepresentsfull-scaleoutput).

See

• Circularprobabilityerror

• Reliability(English:reliability)andvalidity(English:Validity)