What is Error: Definition and 999 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. D

    Propagation of error with sliding window of measurement

    Hello, I don't seem to know how to ask google this question so I thought I'd see if I could get an answer from here. Say I have 400 measurements of some variable. I take a sliding window of 50 events and take the standard deviation of each set of 50 events. That would be 350 measurements. Now...
  2. S

    Error Calculation for Triangular Plate Sides

    Homework Statement Two Sides of a triangular plate are measured as 125mm and 160mm, each to the nearest millimetre. The included angle is quoted as 60+-1. Calculate the length of the remaining side and the maximum possible error in this result My first question is to the nearest millimetre...
  3. D

    MHB Plotting the error vs the change in 1/dx

    In order to plot the error vs the change in 1/dx, I need to integrate the the solution with different a dx and take the max error. However, I don't know how I can set this up in python or matlab. In python, my code for just one dx is: import numpy as np L = 80.0 N = 512 dt = 0.0002 tmax = 10...
  4. ShayanJ

    Calculating Error of w from Errors in x,y,z

    Consider a physical quantity e.g. w,related to some other quantities by w=f(x,y,z) . Imagine an experiment is done for finding the value of w and the measurement errors for x,y and z are known. I want to know what is the standard method for calculating the error in w resulting from the errors...
  5. N

    Error analysis and propagation

    Hi folks, I have a rather simple question on error propagation - I have 2 sets of models, where the results from model are used as variables in the next model. I need to know how to carry forward errors from one to another. Case - Model 1: Y = a*exp(b*X) + c The errors on X (which is a...
  6. S

    Maxwell 3D Fatal Error: Solve Your Issue Now

    hi. I am new at maxwell 2D and 3D. i found some pdfs and examples. I am working on the rotational actuator example which in that pdf 1. and i got an error: Fatal internal error (2:14:49 Eyl 09, 2013) Simulation completed with execution error on server: Local Machine. (2:14:49 Eyl 09, 2013)...
  7. C

    Fortran Fortran Programming Silverfrost Error 112

    I'm new to Fortran, trying to run this program but when I enter the variables it gives me an error 112. Please help me find where is the mistake. I copied the program from an old book. DIMENSION S(50),V(50) ! Element stress and velocity DIMENSION U(51) ! Nodal displacement ! Double...
  8. A

    Error in Griffiths QM: completeness of stationary states

    According to Griffiths QM book, after he derived the stationary state solutions to the Schrodinger equation for a particle in an infinite potential well, which are just functions of sine, he claims that these stationary solutions are orthogonal and complete. I agree that they are orthogonal...
  9. B

    Modified Coulomb model for hydrogen, minimising error

    Homework Statement The ground energy can be approximated as E_{1}^{(1)}\approx-\frac{4b^2}{a_0^2}E_R Find the largest value of b that would be consistent with the ground-state energy of a hydrogen atom that agrees with the predictions of the Coulomb model to one part in a thousand...
  10. G

    Mcnp error the new source has overrun the old source

    mcnp error "the new source has overrun the old source" I am a beginner with MCNP. This error really confused me. Who knows what this error means? Thank you.
  11. K

    Fortran FORTRAN Problem Runtime Error: End of File

    FORTRAN Problem! "Runtime Error: End of File" Hey everyone, back again with another Fortran question. I am getting the runtime error in Fortran "End of Line". I have tried to simply understand what this means, but I am not getting much help from Google. I have pasted my code below, and...
  12. B

    Error in proof for symmetry groups?

    \renewcommand{\vec}[1]{\mathbf{#1}} Here is an excerpt from the text: "[...]Theorem 12.5 The only finite symmetry groups in ℝ^2 are \mathbb{Z}_n and D_n. PROOF. Any finite symmetry group G in \mathbb{R}^2 must be a finite subgroup of O(2); otherwise, G would have an element in E(2) of...
  13. L

    Error analysis/mechanics help appreciated

    State and justify the techniques you would use to reduce the errors of the following. Each explanation should show a clear understanding of why the technique is relevant in the particular situation. 1. Measure the time it takes for a ping pong ball to drop from a height of 50 cm and bounce 3...
  14. L

    Error analysis/mechanics help appreciated

    State and justify the techniques you would use to reduce the errors of the following. Each explanation should show a clear understanding of why the technique is relevant in the particular situation. 1. Measure the time it takes for a ping pong ball to drop from a height of 50 cm and bounce 3...
  15. Tclack

    Fluid Force (Real-Life application) Find my error

    So I'm in the Navy. I work on an aircraft carrier that just went into drydock. The drydock has a large trapezoid door keeping the water out on one side. Our captain wants to know how much force is being held back on that door. I found the dimensions of it and calculated it, but now I'm having...
  16. M

    Estimating measurement error using error from linear regression

    Sorry if I'm in the wrong subforum. This is a rather simple and straightforward question, I hope. I'm doing a measurement that requires me to do a linear regression on data points to get a value of the slope. The slope is the value of the actual property that I am measuring. Assuming...
  17. MarkFL

    MHB Courtney's question at Yahoo Answers regarding Error Bound for approximation methods

    Here is the question: I have posted a link there to this topic so the OP can see my work.
  18. Darth Frodo

    Mean Absolute Percentage Error in R

    Hi all, I'm trying to calculate the M.A.P.E. using the accuracy() function in SDMtools. I have an output of 10.69. I'm not sure if this is 10.69% or 1069% as previously in a different model I had gotten an output of 0.34. If anyone is familiar with this, I would appreciate any help...
  19. G

    Error in dipole moment calculation

    I am calculating the dipole moment of a metal sphere in a uniform electric field E_0 in z-direction. From here I know that the charge density [look at page 15][1] [URL="[PLAIN]http://www.phy.iitb.ac.in/~dkg/PH-102/conductors.pdf"]http://www.phy.iitb.ac.in/~dkg/PH-102/conductors.pdf[/PLAIN]...
  20. H

    Truncation error of the ADI method

    Dear, Can someone tell me with certainty if the truncation error of the general ADI method is of seconder order in time and space?
  21. L

    Fortran Segmentation error form the fortran code

    Hi Forum users I have a velocity autocorrelation code which was made to read a three component velocity vectors and I have modified to read a 9 component stress tensor data. I can compile it successfully but when I try to run it and compute a stress correlation function I get an error: i.e...
  22. A

    Error in perturbation series question

    Suppose we know the perturbation series E = E(\epsilon) = E_0 + \epsilon E_1 + \epsilon^2 E_2 + \ldots converges, where E_0 is a discrete eigenvalue of H_0 and we are considering a Hamiltonian H = H_0 + \epsilon H_1. Does this mean that we know E - E_0 = O(\epsilon) as...
  23. S

    Fortran Porting fortran program-compile error ambiguous use of intrinsic Real

    Hello, I had started an earlier thread on porting this same program to linux. In that thread I had asked about padding (align) issues. It may turn out that the padding messages may only be warnings and I have shelved that problem. A more critical issue is the one error on ambiguous use of...
  24. S

    Coefficient of Determination( Line Best Fit Error)

    https://www.khanacademy.org/math/probability/regression/regression-correlation/v/r-squared-or-coefficient-of-determination Homework Statement So, when determining how effectively a best-fit line describes the variance of a given set of measured data, the Coefficient of Determination is the...
  25. E

    Measurement uncertainty and error

    Suppose we have x plates of wood of thickness (0.0150 \pm 0.0002) \text{ m} and we wish to stack them into a pile of height (1.000 \pm 0.001) \text{ m}. The number of plates x required is then x = \dfrac {1.000 \pm 0.001}{0.0150 \pm 0.0002} \, . How many plates will certainly fit in the...
  26. H

    Calculating error with known to be innaccurate decimals

    My book says: The bit I don't get is Why? Apply this logic to one of the numbers at random for arguments sake, let's say the first number .234673, it couldn't be .2346735-.2346739 or else it would have been rounded to .234674. It's true value (if it's greater) has to lie somewhere between...
  27. C

    Conditional Probability: an incorrect error detection

    Homework Statement From Mathematical Statistics and Data Analysis 3ed, Rice 1.8 #61 Suppose chips are tested and the probability they are detected if defective is 0.95, and the probability they are declared sound if they are sound is 0.97. If 0.005 of the chips are faulty. What is the...
  28. X

    Find the error in a linear regression

    Hi, I am trying to understand how I find the error in linear regression, and what to do with it. I am using linear regression to predict the time of execution based on the size of the input and the number of tasks used in the computer to get the result. 1 - In a linear regression, I calculate...
  29. T

    Question on the error function and when I can evaluate it numerically

    Homework Statement I'm working with a particularly malicious mass model function given as: λ^n*exp(-x^2)*(λ+x)^-n, λ=constant, n=constant (1.8 for those who care) The first round of integration by parts using u=(λ+x)^-n, du=-n(λ+x)^(-n-1)dx dv=exp(-x^2), v=sqrt(pi)/2*erf(x) Gives me...
  30. N

    Fortran Integrating User-Defined Functions in Fortran 95: Troubleshooting Runtime Errors

    Hi! I'm trying to write a function that will integrate a user given function. I am having trouble with reading the function. Here is a section of my code: function f(x) implicit none real :: x,f,p print *,'Type a probability density function' read *, p !It doesn't like line 34... f = p...
  31. jaumzaum

    Investigating an Unexpected Error: What's Wrong?

    What is wrong?? Hi, I want to know where is the mistake in the statement below (I really don't know what is wrong, but it is obviously wrong) \frac{\partial ^{2}x}{\partial t^{2}} = \frac{\partial ^{2}x}{\partial x^{2}} (\frac{\partial x}{\partial t} )^{2} But...
  32. N

    Fortran Getting an unclassifiable statement error in Fortran 95

    Getting an "unclassifiable statement" error in Fortran 95 I am trying to integrate the function x from 0 to 1. Here is my code: program myownmonte !This program will integrate the function x from 0 to 1 implicit none real :: ans0,y,f,x,xmax integer :: icount,nmax,i,iseed iseed = 89237...
  33. S

    [2D FDTD TFSF problem] got error in result but don't know why

    HI all, I did wrote codes for 2D FDTD TFSF TMZ mode using yee algorithm. But the output I got was not as expected. The curve was bended, and major leaking after some time when approaching ilast, jlast. Can anyone help me to analyze the output graph eg, why the leaking happened, and why the...
  34. R

    Newtons Cooling problem/ possible error in book.

    I have a book called REA 's problem solvers: Differential Equations Year 2004 and the problem 12-14 on page 244 might have problems with it and I want to ask to see if anyone else thinks so. The problem is basically Newton's cooling where they ask to find T - T_o = (T_i - T_o) e^(-kt)...
  35. J

    Error from Force 2.0 G77 but not from G77 Mingw

    Array `cm' at (^) is too large to handle I get this error/warning when compiling with the Force 2.0 G77 compiler. However, I do not get this with my MinGw G77. This is the first program I have found that causes this error with Force 2.0, but I would like to fix it. Any ideas why it would...
  36. M

    Voltmeter relative error question. (Computer Controlled Measurement)

    Homework Statement You measure 50V with a voltmeter, which has 300V as the max. input voltage. What will be the relative error (h%) of the measurement? Homework Equations The Attempt at a Solution hi i divided 50v / 300 V and get = 1,66 and divided it by 100 to get relative error...
  37. C

    Calculating the strain in three different ways - experimental error?

    I've recently done an experiment where I've obtained the strain of a channel section beam in bending. I used a strain gauge to get the strain from the midspan and also used dial gauges to get the deflections of the beam under different loading conditions. Along with the readings I've...
  38. M

    How Do I Perform Error Analysis in a Pendulum Experiment?

    Error Analysis/Significant Figure help please! Hi Physics Forums, I have an assignment due very soon and I have completed everything, bar error analysis. I have been told that we need to calculate relative and absolute errors or something along those lines and I have NO IDEA what I am doing...
  39. ikihi

    Error in my textbook? scientific notation conversion

    Homework Statement The question is: The Earth formed 4.57 x 10^9 years ago. What is this time in seconds? The answer the textbook is giving is 1.44x10^17 seconds. The answer I keep getting is 1.44x10^15 seconds. Is the textbook wrong or am i wrong?
  40. F

    MCNP error about dose claculation of phantom

    Hello,everyone.Lastly,I use MCNP to claculate the dose distribution of CT phantom,but when I run my code,I get a message that says ' bad trouble in subroutine newcel of mcrun source particle no. 18859 starting random...
  41. S

    Optimizing Simpson's Rule for Error Bound: Finding the Minimum Value of n

    Homework Statement Calculate the value of n so that the approximation is within 0.0001. b = 2, a = 1. f(x) = 1/x. Homework Equations f4(x) = 24/x^5 (Think this is correct) Error <= (b-a)^5/180n^4(MAXx [a,b](f4(x)) The Attempt at a Solution Well, 24/x^5 obtains it's max at x =1...
  42. D

    Why am I getting a fatal error in MCNP with xsdir missing cross-section tables?

    fatal error. *** cross-section tables are missing from xsdir 10001.70m 10002.70m 10003.70m ... bad trouble in subroutine ixsdir of imcn cannot continue with missing cross-section table(s). is the message I am getting. I have created a link using ln -s...
  43. B

    Does a hamming code always corrects one error and detect 2 errors ?

    does a hamming code always corrects one error and detect 2 errors ? and is the distance always 3 ? I know that that is true for (7,4) hamming code but does that apply to a (11,7) or (15,11) ? if not please let me how to get the answers
  44. E

    Expressing probability of bit error

    Homework Statement I need to the probability of bit error in terms of integrals and terms of conditional probabilities. Its a bipolar system using threshold detection https://www.physicsforums.com/attachment.php?attachmentid=58542&stc=1&d=1367888259 Homework Equations probability of...
  45. P

    Refractive index experiment/finding error on graphs

    I'm writing a physics practical report on the refractive index of glass. We performed an experiment in which we measured the incident angle and the refractive angle of light entering a glass block. When plotting sin(ϴa) against sin(ϴg) with the y-intercept as 0 (to satisfy snell's law...
  46. C

    Solving for a variable inside the error function?

    i need to solve for a variable inside the error function on excel, is there an opposite function i can use to accomplish this? example: y = sqrt(x-t) -> x = t+y^2 except instead of a sqrt( ) I have erf( ) **this is not a math class so I don't have to get into breaking it down into the...
  47. P

    What is the cause of Verilog error message 10159 in my binary calculator code?

    I'm currently working on a project to create a binary calculator using verilog, which I will eventually program onto a DE2 FPGA board. I am trying to wrte my code but I keep getting the following error message. "Error (10159): Verilog HDL error at calculator.v(37): "Display" is not a task or...
  48. O

    Hex Meshing Error: Do I Need to Partition the Part?

    I am attempting to mesh this part using "hex" elements but I always receive an error. Am I supposed to partition the part? If so how do I do that? Thanks for you help P.S. I attached related documents to this post
  49. S

    Vandermonde Matrix and an Error Vector

    format long n = inputdlg('Please enter a series of numbers separated by spaces/commas: ') numbers = str2num(n{1}); X = 0 V = fliplr(vander(numbers)) r_size = size(V,2); c_size = size(V,1); B = 1+(r_size./numbers) X = B/V Here's what I have so far. I've been running the program with...
  50. H

    Possible error found in Keith Devlin's book The Math Gene Help?

    Possible error found in Keith Devlin's book "The Math Gene" Help? Homework Statement In the section "What is mathematics?" of Keith Devlin's book The Math Gene, he explains to the layman the purpose of abstractions. Devlin uses an example from group theory of symmetry to explain a point...
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