Name: how measurement errors affect results
Uploaded: 2023-04-30T12:12:04.000Z
Duration: 1 min 20 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Nature of Science

SC.912.N.1

SC.912.N.1.4

Random and Systematic Errors

Errors in the measurement process are a common problem. Such errors may fall into two categories: Random and Systematic.
Random errors are the result of inconsistency in the measuring process or variations in the quantity being measured. These result in fluctuations, too high or too low, around the true value.
Consider a scientist measuring the length of an earthworm using a caliper. Inconsistency of the scientist to read the scales correctly, or continuous body movement of the earthworm during the measurement, may result in incorrect length measurements.
Random error cannot be avoided, however, it can be averaged out with repeated trials.
Systematic errors are the results of a persistent issue and lead to a consistent discrepancy in measurement. These errors tend to be either all too high or all too low compared to the true value. For instance, weights being measured using an improperly calibrated weighing balance.
These are predictable and mostly instrument-related. However, unlike random error, it cannot be averaged out with repeated measurement.

willekeurige en systematische fouten

Wetenschappers doen altijd hun best om metingen met de grootst mogelijke nauwkeurigheid en precisie vast te leggen. Soms komen er echter fouten voor. Deze fouten kunnen willekeurig of systematisch zijn. Willekeurige fouten worden waargenomen als gevolg van de inconsistentie of fluctuatie in het meetproces, of variaties in de hoeveelheid zelf die wordt gemeten. Dergelijke fouten variëren van groter of kleiner dan de werkelijke waarde bij herhaalde metingen. Stel je een wetenschapper voor die de lengte van een regenworm meet met behulp van een liniaal. Willekeurige fouten in dit meetproces kunnen het gevolg zijn van de inconsistente methode waarbij de wetenschapper de weegschaal afleest, of als de regenworm beweegt. Willekeurige fouten kunnen niet worden vermeden; het kan echter met herhaalde pogingen worden uitgemiddeld. Systematische fouten komen voort uit een hardnekkig probleem en resulteren in een consistente discrepantie in de metingen. Deze fouten zijn meestal groter of kleiner dan de werkelijke waarde. Deze zijn voorspelbaar en meestal instrumenteel van aard. Een onjuist gekalibreerde weegbalans kan bijvoorbeeld voortdurend voorwerpen wegen die zwaarder zijn dan hun werkelijke waarde. In tegenstelling tot willekeurige fouten kunnen systemische fouten niet worden uitgemiddeld door herhaalde metingen. Deze tekst is overgenomen uit <a href="https://openstax.org/books/chemistry-2e/pages/1-5-measurement-uncertainty-accuracy-and-precision">Openstax, Chemistry 2e, Sectie 1.5: Meetonzekerheid, nauwkeurigheid en precisie.</a>

Willekeurige en systematische fouten

Scientists always try their best to record measurements with the utmost accuracy and precision. However, sometimes errors do occur. These errors can be ...

Education

JoVE Core

Physics

Natuurkunde

Unit 1

Onderdeel 1

Units, Dimensions, and Measurements

Eenheden, dimensies en metingen

KEY TERMS AND CONCEPTS

BELANGRIJKE TERMEN EN CONCEPTEN

how measurement errors affect results

Measurement errors can change how accurate and precise a result appears. Scientists try to record measurements as carefully as possible, but errors can still happen. These errors are usually random or systematic.

Random errors come from inconsistency or fluctuation in the measuring process. They can also come from changes in the quantity being measured. In repeated measurements, random error may make a value appear greater than the true value one time and less than it the next.

A simple example is measuring the length of an earthworm with a ruler. The error could come from reading the scale differently each time. It could also happen if the earthworm moves during the measurement. Random error cannot be avoided, but repeated trials can help average it out.

Systematic errors come from a persistent problem that causes a steady measurement shift. They usually make results consistently greater than the true value or consistently less than it. These errors are predictable and are often instrumental in nature.

An improperly calibrated weighing balance is one example of systematic error. It may keep weighing objects heavier than they really are. Unlike random error, systematic error cannot be averaged out by repeating the measurement.

How Measurement Errors Affect Results

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random and systematic errors

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key terms and concepts

Learn how random and systematic errors affect scientific measurements, with clear examples like a moving earthworm and an uncalibrated balance.

How Measurement Errors Affect Results | JoVE K12

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SC.912.N.1.7

How Measurement Errors Affect Results

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