# Multiplying And Dividing Error Propagation

## Contents |

or more quantities, each with their individual uncertainties, and then combine the information from these quantities in order to come up with a final result of our experiment. How can you state your answer for the combined result of these measurements and their uncertainties scientifically? The answer to this fairly common question propagation of error physics depends on how the individual measurements are combined in the result. We will treat each case separately: error propagation calculator Addition of measured quantities If you have measured values for the quantities X, Y, and Z, with uncertainties dX, dY, and dZ, and your final error propagation square root result, R, is the sum or difference of these quantities, then the uncertainty dR is: Here the upper equation is an approximation that can also serve as an upper bound for the error. Please note that the rule is the same

## Error Propagation Inverse

for addition and subtraction of quantities. Example: Suppose we have measured the starting position as x1 = 9.3+-0.2 m and the finishing position as x2 = 14.4+-0.3 m. Then the displacement is: Dx = x2-x1 = 14.4 m - 9.3 m = 5.1 m and the error in the displacement is: (0.22 + 0.32)1/2 m = 0.36 m Multiplication of measured quantities In the same way as for sums and differences, we can also state the result for the case of multiplication and error propagation chemistry division: Again the upper line is an approximation and the lower line is the exact result for independent random uncertainties in the individual variables. And again please note that for the purpose of error calculation there is no difference between multiplication and division. Example: We have measured a displacement of x = 5.1+-0.4 m during a time of t = 0.4+-0.1 s. What is the average velocity and the error in the average velocity? v = x / t = 5.1 m / 0.4 s = 12.75 m/s and the uncertainty in the velocity is: dv = |v| [ (dx/x)2 + (dt/t)2 ]1/2 = 12.75 m/s [(0.4/5.1)2 + (0.1/0.4)2]1/2 = 3.34 m/s Multiplication with a constant What if you have measured the uncertainty in an observable X, and you need to multiply it with a constant that is known exactly? What is the error then? This is easy: just multiply the error in X with the absolute value of the constant, and this will give you the error in R: If you compare this to the above rule for multiplication of two quantities, you see that this is just the special case of that rule for the uncertainty in c, dc = 0. Example: If an object is realeased from rest and is in free fall, and if you measure the velocity of this object at some point to be v = - 3.8+-0.3 m/s, how long has it been in free fall? Answer: we can calcula

Google. Het beschrijft hoe wij gegevens gebruiken en welke opties je hebt. Je moet dit vandaag error propagation average nog doen. Navigatie overslaan NLUploadenInloggenZoeken Laden... Kies je taal. Sluiten Meer

## Error Propagation Excel

informatie View this message in English Je gebruikt YouTube in het Nederlands. Je kunt deze voorkeur

## Error Propagation Definition

hieronder wijzigen. Learn more You're viewing YouTube in Dutch. You can change this preference below. Sluiten Ja, nieuwe versie behouden Ongedaan maken Sluiten Deze video is niet http://lectureonline.cl.msu.edu/~mmp/labs/error/e2.htm beschikbaar. WeergavewachtrijWachtrijWeergavewachtrijWachtrij Alles verwijderenOntkoppelen Laden... Weergavewachtrij Wachtrij __count__/__total__ 11 2 1 Propagating Uncertainties Multiplication and Division Lisa Gallegos AbonnerenGeabonneerdAfmelden5252 Laden... Laden... Bezig... Toevoegen aan Wil je hier later nog een keer naar kijken? Log in om deze video toe te voegen aan een afspeellijst. Inloggen Delen Meer Rapporteren Wil je een melding indienen over de https://www.youtube.com/watch?v=qzfOdrS0thA video? Log in om ongepaste content te melden. Inloggen Transcript Statistieken 5.049 weergaven 41 Vind je dit een leuke video? Log in om je mening te geven. Inloggen 42 1 Vind je dit geen leuke video? Log in om je mening te geven. Inloggen 2 Laden... Laden... Transcript Het interactieve transcript kan niet worden geladen. Laden... Laden... Beoordelingen zijn beschikbaar wanneer de video is verhuurd. Deze functie is momenteel niet beschikbaar. Probeer het later opnieuw. Gepubliceerd op 4 sep. 2014 Categorie Mensen & blogs Licentie Standaard YouTube-licentie Laden... Autoplay Wanneer autoplay is ingeschakeld, wordt een aanbevolen video automatisch als volgende afgespeeld. Volgende Calculating Uncertainties - Duur: 12:15. Colin Killmer 12.513 weergaven 12:15 Significant Figures Rules Explained Rounding Decimals, Zeros, Digits Uncertainty Chemistry & Physics - Duur: 1:36:02. The Organic Chemistry Tutor 998 weergaven 1:36:02 Calculating Uncertainty (Error Values) in a Division Problem - Duur: 5:29. JenTheChemLady 3.444 weergaven 5:29 Lesson 11.2a Absolute vs. % Uncertainty - Duur: 12:58. Noyes Harrigan

Engineering Medicine Agriculture Photosciences Humanities Periodic Table of the Elements Reference Tables Physical Constants Units and Conversions Organic Chemistry Glossary Search site Search Search Go back http://chem.libretexts.org/Core/Analytical_Chemistry/Quantifying_Nature/Significant_Digits/Propagation_of_Error to previous article Username Password Sign in Sign in Sign in Registration Forgot password Expand/collapse global hierarchy Home Core Analytical Chemistry Quantifying Nature Expand/collapse global location Propagation of Error Last updated 20:33, 14 May 2016 Save as PDF Share Share Share Tweet Share IntroductionDerivation of Exact FormulaDerivation of Arithmetic ExampleCaveats and WarningsDisadvantages of Propagation of Error ApproachTreatment of Covariance TermsReferencesContributors Propagation error propagation of Error (or Propagation of Uncertainty) is defined as the effects on a function by a variable's uncertainty. It is a calculus derived statistical calculation designed to combine uncertainties from multiple variables, in order to provide an accurate measurement of uncertainty. Introduction Every measurement has an air of uncertainty about it, and not all uncertainties are equal. Therefore, the ability to properly multiplying and dividing combine uncertainties from different measurements is crucial. Uncertainty in measurement comes about in a variety of ways: instrument variability, different observers, sample differences, time of day, etc. Typically, error is given by the standard deviation (\(\sigma_x\)) of a measurement. Anytime a calculation requires more than one variable to solve, propagation of error is necessary to properly determine the uncertainty. For example, lets say we are using a UV-Vis Spectrophotometer to determine the molar absorptivity of a molecule via Beer's Law: A = ε l c. Since at least two of the variables have an uncertainty based on the equipment used, a propagation of error formula must be applied to measure a more exact uncertainty of the molar absorptivity. This example will be continued below, after the derivation (see Example Calculation). Derivation of Exact Formula Suppose a certain experiment requires multiple instruments to carry out. These instruments each have different variability in their measurements. The results of each instrument are given as: a, b, c, d... (For simplification purposes, only the variables a, b, and c will be used throughout this derivation). The

be down. Please try the request again. Your cache administrator is webmaster. Generated Thu, 20 Oct 2016 20:51:14 GMT by s_nt6 (squid/3.5.20)