What is Errors: Definition and 346 Discussions

An error (from the Latin error, meaning "wandering") is an action which is inaccurate or incorrect. In some usages, an error is synonymous with a mistake.
In statistics, "error" refers to the difference between the value which has been computed and the correct value. An error could result in failure or in a deviation from the intended performance or behavior.

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  1. K

    Can Differentials and Errors be Split in Calculus?

    I asked a question a few weeks ago about 'splitting' the derivative. The thread can be found https://www.physicsforums.com/showthread.php?p=3581188#post3581188" The answer to why it can not be split is because dx does not exist, it is simple a notation and not a fraction. However, I just...
  2. S

    Propagation of errors addition numbers without uncertainty

    Homework Statement I am having trouble calculating uncertainty when a number is added to a value with uncertainty. M = 350g a = 0.624 \pm 0.001 µk = 0.07 g = 9.80 m/s2 Homework Equations T = M*a + µk*M*g The Attempt at a Solution T = (350g)*(0.624 m/s2) +...
  3. M

    Possible Errors Made Regarding Polarity and Intermolecular Bonds

    Hello, I wouldn't necessarily regard this as homework. While these are errors I believe I have found within an online course in which I am currently enrolled, my asking is simply carried out with interest in acquiring an accurate knowledge of entry-level chemistry. While studying polar...
  4. P

    Calculating errors (propagation)

    Completely new to the concept of errors and don't know how to approach this... Calculate value and error in Z Z= 2AB^2/C Where A= 100 Error in A= +/- 0.1 B= 0.1 Error in B= +/- 0.005 C= 50 Error in C= +/- 2 Plugging in the numbers Z= 0.04 How do you carry the errors...
  5. H

    Errors with s-function level 1 in simulink

    Hi all, I am modeling a separator model with pressure and water level as 2 variables. I first made an m-file(hamda.m) with ode23tb, which is working( 4 plots: pressure, water level, flow of liq output and flow of gas output. then I used an level 1 s-function( gabileh) applying the...
  6. J

    Normally distributed data errors

    Homework Statement Hello If my data errors are normally distributed, is this the same as the data being normally distributed? I mean, by "normally distributed data errors" is meant that with 68% confidence the data lies within the true value?
  7. N

    Errors by great minds in theoretical physics

    Hello, It is sometimes stated that the great minds of theoretical physics also made many mistakes, and were not afraid to do so, since you have to dare to make mistakes if you want to do some original thinking; but the errors are forgotten, and the good things are remembered. Now my question...
  8. J

    The errors leading to the discrepancies between q-value

    I operated an experiment to find out the Q-factor of the LCR circuit. I worked out the q-value using three methods: 1. Q=1/R*sqr(L/C) where R=the total resistance of the circuit>>Q= 14.98 2. Q= Vc/Vr where Vc is the voltage across the capacitor and Vr is the voltage across the total...
  9. D

    Errors in computing the Crank-Nicolson Method

    Hi all! Having decided to return to coding some of the physical problems that I require solving(in lieu say, of Mathematica), I endeavored to adapt the Crank-Nicolson to my needs, but, in order to test my algorithm, I had first attempted to resolve the common and trivial heat equation, in one...
  10. N

    Young's doublt slit experiment - Systematic and random errors -

    Young's doublt slit experiment - Systematic and random errors - URGENT! Homework Statement Can anybody think of any other systematic and/or random errors for young's double slit experiment when using it calculate the wavelength of a light source? I have an inclass prac write up tomorrow and...
  11. Evo

    Undetweetable, an archive of errors and regrets

    This sounds lovely. http://news.yahoo.com/blogs/technology-blog/undetweetable-keeps-those-embarrassing-updates-alive-even-ve-012135771.html
  12. F

    Mathcad errors galore (symbolic evaluation)

    Hello, I'm trying to use mathcad to do Rayleigh-Ritz approximation of the critical elastic buckling load of a joists top chord. The joists support a standing seam roof which acts to stabilize the top chord from out of plain buckling. In order to approximate the buckled shape, I chose to use...
  13. J

    Fixing VHDL Errors for Traffic Light System

    Hi I've got a problem with VHDL code its comming up with a lot of errors saing that there's undefined symbols, so I am pretty sure that the error is to do with defining things/instantiation, below is all the code for both the files that are being used...
  14. C

    Speed of Sound - Errors and Enhancements

    I need sources of error (4) , and some enhancements for accuracy (4) for a lab experiment involving speed of sound. The experiment is as follows (as I have done it) 1. Using water to move a tube up/down to look for the first antinode. 2. Used a 512 Hz tuning fork to create the vibrations. 3...
  15. H

    What mistake did Mindy make when solving this quadratic equation?

    Homework Statement Mindy solves the problem (x+4)(x-3)=8 by setting x+4=8 and x-3=8, thereby getting the solutin x=4 from both equations. she checks her answer by substituting x=4 into the original equation and finds that it works. She concludes that this quadratic equation has only one...
  16. T

    MATLAB Fixing MATLAB Loop Error in TSR Calculation for VAWT

    I'm trying to write a MATLAB code but I get an error message which I'm not sure why. The code is follows as, %%%%% Code %%%%% for i = 1:1:v; for j = 1:0.1:a TSR(i,j)=wR/i; end end %%%%% Code %%%%% Here 'a' is taken as...
  17. M

    How would you minimise these gravimetric analysis errors?

    Homework Statement -precipitate not being pure e.g. other ions (present in the precipitate increasing the weight of the precipitate) - in an experiment where BaSO4 is used and some of it isn't dissolved in the wash due to the 'low solubility' of BaSO4 - resulting in a lower weight...
  18. Phrak

    Lorentz Invariant Vectors and Grammatical Errors

    A vector in special relativity is the quantity: V = V^\mu \hat{e_\mu} On a change of coordinates, the basis vectors co-vary with the coordinate derivatives: \hat{e_\mu'} = \frac{\partial x_\mu'}{\partial x_\mu} \hat{e_\mu} The vector elements are the opposite. They are said to be...
  19. M

    Rinsing Errors in Back Titration (Finding Nitrogen in Fertiliser)?

    Homework Statement Just need someone to confirm whether I am right for this (The prac is using back titration to find the amount of Nitrogen in Fertiliser) How would the following affect your experiment: Burette, pipette and volumetric flask are rinsed with the wrong solution i.e water...
  20. G

    INS : Gyroscope errors : transport wander, apparent drift , coriolis effect ?

    can anyone please explain me following errors of gyroscopes used in inertial navigation systems of aircraft : a) what is transport wander , how actually it happens ? b) what is apparent drift in gyroscope ? c) what is coriolis effect and how it causes errors in gyroscopes ?
  21. R

    Particle size distribution/histogram errors.

    I posted this elsewhere but probably in the wrong topic so have reposted here. Okay, so I have obtained a particle size distribution of diesel exhaust particles on a SEM. Data has been plotted and fitted with a lognormal distribution. Although it isn't a usual path to take I have been told I...
  22. M

    Exploring the Errors of RK4 Method for y' = -2y + x, y(0) = 1

    Homework Statement Consider the initial value problem y' = -2y + x, y(0) = 1 The analytical solution is y(x) = (1/2)x2-(1/4) + (5/4)e-2x a. Approximate y(0.1) using one step and the RK4 method. b. Find a bound for the local truncation error in y1. c. Compare the error in y1 with the...
  23. S

    Proving the Normal Law of Errors: A Guide

    How to prove the normal law of errors?
  24. T

    Poisson errors for the distribution of galaxies?

    Poisson errors for the distribution of galaxies?? Hi, I have some data regarding the distribution of galaxies of varying mass in different density regions of the Universe, from which I have a mass functions for each region. I would now like to introduce some errors so I can determine whether...
  25. S

    Probability of a page being free from printing errors

    A book of 100 pages contains 200printing errors distributed randomly among the pages. the probability that one of the pages will be completely error free is closest to a)67% b)50% c)25% d)13% The Attempt at a Solution I tried to calculate total number of possible events. I...
  26. O

    Help Calculate Errors: Lambda & n Uncertainty on 'n2

    Homework Statement I need to find the uncertainty on "n2" I have the uncertainty on lambda, n1 is not a variable - its 2, R is a constant. Only things that have errors are lambda and n Homework Equations The Attempt at a Solution Tried working out using calculus, but every...
  27. J

    Troubleshooting Lab Errors with a Ballistics Pendulum

    Hey guys, I was just wondering what is an error during a lab? I always get these parts wrong on my lab, mainly because I don't know of any errors that are occurring in a lab. For my lab I was using a ballistics pendulum and sometimes the rod wouldn't pull back right or shoot right. Would that...
  28. S

    What Are Common Mistakes When Programming an Elevator System in C++?

    Homework Statement This program simulates the actions of two elevators in a building. The building has MAXFLOOR floors - make this a program constant and set it to 15. You need to write an Elevator class. This class will have only one member variable, which is the floor of the building on...
  29. I

    Errors on velocities and distance.

    Homework Statement A galaxy has velocity due to Hubble (Ho) expansion, and in addition a peculiar velocity (AN this is the velocity of the galaxy in its local enviroment/gravitational potential) this vel. is 450Km/s I need to estimate the the minimum distance at which a galaxy must be in...
  30. S

    Fortran Help with Fortran IV to Fortran77 Conversion Errors

    I have a program written in Fortran IV and tryed to run it with fortran77(g77). Nevertheless it could be not problem in fortran IV it make some errors in fortran77. I am not programmer but trying to learn some. Here is the errors that compiler fortran77 is wrote: found.f: In program...
  31. G

    Finding the error on an intercept, given two points with errors.

    Homework Statement (The question is about micro vertex detectors, but I've distilled it into what needs to be done) You have two points (x1,y1 and x2,y2), assumed to lie on a straight line. The points have a one sigma uncertainty of d. x1 and x2 are separated by a distance L (much greater...
  32. E

    Wikipedia math section full of errors

    wikipedia is full of errors
  33. A

    The treatment of errors and uncertainties?

    I am confused over how to work with errors and uncertainties. So far when dealing with a small number of measurements I have used the partial derivative method to calculate the final error in my result e.g. if my result is E=mgh \text{ then assuming no error in g my uncertainty is }...
  34. 1

    Kinematics Worksheet - Velocity/Acceleration Problems - Please Point Out Errors

    Homework Statement Homework Equations a=v/t v=d/t The Attempt at a Solution Same as above in number 1, all work is shown. I know for a fact that the two tables on the very top are correct because my teacher did them on the board, as well as the graph. Only the rest of the...
  35. R

    Standard Errors and Margin of Error

    Hello All, I am having to brush up on my stats for work and it's been a long time (>10yrs) since I've had to even think about this stuff. I could do with some help clarifying a specific point about standard errors and margin of error. An example I am looking at from my old notes is this: the...
  36. Z

    Standard errors in surface areas and volumes?

    I have to finish this one question that I have come across and I am having a bit of trouble figuring out where to go from what I havee done. The Q is: A copper cylinder is 5.82 +/- 0.06 cm long and has a radius of 2.53 +/- 0.04 cm. Using the appropraite formula, Question Details a) Find...
  37. C

    Physics lab, calculating/combining errors

    I just started the semester off in physics lab and I am so rusty. I did three perfectly okay by myself but these last three I can't seem to figure out. Any help on the direction to take with these is appreciated! c) T = 0.433 ± 0.004 s. Calculate T^2 andΔT^2. d) Given d = vt, v = 55...
  38. X

    Uncertanties and errors question

    *Before I start, I just want to say that this is only my second day in IB Physics. I had never taken Physics at in in high school prior to IB Physics, so I really had to read up and pretty much self-teach myself a bit of it over the summer. Of course, even now I still have absolutely no idea...
  39. I

    Comp Sci First time programming ever and my first project has 1-21 errors in c++

    Homework Statement #include <iostream> using namespace std; int main() { int firstNo;// first number is stored here int secondNo, int resultAdd,// variable for result when first number and second number are added int resultSub,// variable for result when first number and second...
  40. M

    Troubleshooting Compilation Errors: Why Won't My Program Compile?

    Tell me why am i not able to compile this program, the terminal lists various errors http://tinypic.com/r/1zxtm5h/7
  41. A

    Errors and precautions when discharging a capacitor?

    Can someone tablet some errors(better with improvement) or precautions when discharging a capacitor? The experiment aims to investigate the decay curve of charge/current when discharing a capacitor. Thanks!
  42. G

    Errors and approximation question

    Homework Statement In an inertial navigation system on switching ON an intial error of 0.0001m/s^-2 exists in one direction. After 30 minutes an additional error of -0.00005m/s^-2 in acceleration builds up. The system navigates for 2hrs 30 minutes after switching ON. compute the error in...
  43. P

    Why is the wavefront error non-zero at the image plane in Zemax?

    Hi all I was searching the web to clarify a conceptual issue regarding the wavefront map in Zemax optical design software. Wavefront map in Zemax is suppose to tell us about the aberrations in the optical system. If I propagate a plane parallel beam in air from the object (at infinity) to...
  44. Q

    How Do We Calculate Equivalent Resistance with Measurement Errors?

    we write \frac{1}{R}=\frac{1}{R_1}+\frac{1}{R_2} where R is the equivalent resistance of R_1 and R_2. Let there is an error in the measurements of R_1 and R_2 of \pm \Delta R_1 and \pm \Delta R_2 respectively. Is it correct that \frac{\Delta R}{R^2}=\frac{\Delta...
  45. wolram

    Is the Conventional Wisdom About the Universe Wrong?

    http://www.sciencedaily.com/releases/2010/06/100613212708.htm ScienceDaily (June 14, 2010) — New research by astronomers in the Physics Department at Durham University suggests that the conventional wisdom about the content of the Universe may be wrong. Although at the bottom of the page he...
  46. M

    Type 1 and type 2 errors?

    Let's say I'm testing anti-spam software. The number of false positives (aka, friendly messages misidentified as spam, for those who don't know the term) is 40. The number of false negatives (spam messages misidentified as friendly) is also 40. I'm testing 100 messages. How many more...
  47. T

    Calculating errors in Functions of two variables Taylor Series

    Homework Statement From the taylor series we can replace x =x_{0} + h but how does \delta f = f(x_{0} + h, y_{0} + k) - f(x_{0},y_{0}) become \delta f = hf(x_{0}, y_{0}) + kf(x_{0}, y_{0}) I can see the first step, but how do you get it to the second?Homework Equations The Attempt at a Solution
  48. O

    PDF of distance between measured coordinates with normally distr. errors

    hi, the problem i have is this: consider a line segment L of length d in R^3. the projection of the endpoints of L on a fixed plane can be determined with an error that is normally distributed, and the errors for the two endpoints needs not to be equal. Assuming that L is randomly oriented...
  49. S

    Introducing Gaussian errors to data (Matlab)

    Homework Statement I need to introduce Gaussian errors to a set of velocity measurements. The errors should have mean zero and standard deviation .2. v = [4.6 3.8 7.2 9.7 6.4]; The Attempt at a Solution I tried to use Matlab's imnoise command (J=imnoise(v,'gaussian',0,.04), but...
  50. F

    Weighted average with uneven errors

    Cant seem to find information on this anywhere... If I want to average two values with errors, say x1 = 10 +/- 2 x2 = 12 +/- 4 I would do a regular weighted average that would reflect the fact that x1 is a more precise measurement. But what if my errors are asymmetric? So if I had...
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