What is Error: Definition and 998 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. danielhaish

    B How addition of vectors works if every force is quantized

    Assuming two forces applied on an object in two vector one horizontal to the object and the other vertical, By vector addition the resulting vector would be in 45 degrees. (0,1) + (1,0) = (1,1) So the object acceleration direction would be as the following graph. But if the force that...
  2. F

    I Uncertainties accumulate when measuring longer lengths?

    Hello, It is clear that as distance being measured increases, more graduations are needed to represent a unit of measure for such distance. Each graduation in a measuring device is subject to uncertainty and error, and these errors and uncertainties accumulate with the increase in the number of...
  3. Sam Groves

    DI controller vs no controller

    If we use a DI controller the error doesnt get better.Regarding the error it is the same as we didnt have any controller at all.But does the DI controller improve the recovery time or not to not having any controller at all?
  4. B

    I Inductance Measurement: Error Due To Series Resistance

    Hi! Please refer to the word file. I am thinking of measuring inductance of an inductor by applying a DC voltage onto it. Then, calculate L = V/(di/dt). I wonder if the series resistance (R) of the voltage source plus of the inductor under test would cause much error. So, I derive the...
  5. P

    I On error estimates of approximate solutions

    I'm reading Ordinary Differential Equations by Andersson and Böiers. They give an estimate for how the difference between an exact and an approximate solution propagates with time. Then they give an example where they encourage the reader to check that this estimate holds. When I do that, I get...
  6. S

    Converting MeV/c^2 to kg

    (1672 MeV/c^2) * c^2 = 1.505 * 10^20 MeV = 1.505 * 10^26 eV = 2.41 * 10^7 J Since E = mc^2, m = E/c^2 Therefore, m = 2.41 * 10^7 / (3 * 10^8)^2 = 2.68 * 10^-10 kg But the answer is 2.97 * 10^-27 kg Help! What is wrong with my logic?
  7. C

    I Error on a weighing scale due to wrong size

    If you have say a 15 centimetre long piece of rigid plastic and the weighing scale's tray is only 10 centimetres, what is an estimate of the error that introduces in the measurement assuming the weight is still within normal parameters for the weighing scale. I was wondering what the approximate...
  8. S

    Is Fedoraforum.org Experiencing a 403 Error?

    For the past few days I get a 403 error when trying to access fedoraforum.org (using Firefox). Is anyone else having this problem?
  9. K

    MCNP Problem - Bad character in column 2

    hello , I am getting an error that reads as follows: 1 PX 12.5 bad trouble in imcn in routine ckchar bad character, probably a control character, in column 2Cell cards 1 0 1 -2 -7 8 10 -9 imp: n=1 2 0 2 -3 -7 8 10 -9 imp: n=0 3 0 3 -4 -7 8 10 -9 imp: n=1 4 0 4 -5 -7 8 10 -9 imp: n=0 5 0 5 -6 -7...
  10. dlgoff

    Experiencing PF server time outs today?

    @Greg Bernhardt I've been getting a lot of connection timed out errors. Anything special going on at PF? Still using Windows 7. This is just satarted happening today.
  11. A

    A Standard error of the coefficient of variation

    What is the standard error of the coefficient of variation in an exponential distribution?
  12. CaliforniaRoll88

    Does the book have an error in the addition of these two vectors?

    (a) $$\vec A = -\vec M+2\vec N=26\hat a_x+10\hat a_y+4\hat a_z$$ Unit Vector Formula $$\hat a_A=\frac{26\hat a_x+10\hat a_y+4\hat a_z}{\sqrt {26^2+10^2+4^2}}$$ $$0.923\hat a_x+0.355\hat a_y+0.142\hat a_z$$ The book gives ##0.92\hat a_x+0.36\hat a_y+0.4\hat a_z## Not sure how the book get 0.4 for...
  13. K

    I Confused about using Monte Carlo for error estimation

    Hello! I have 2 probabilities ##p_1## and ##p_2## which governs the probability of measuring some events. I measure event 1 N times and get ##N_1## counts and event 2 N times and get ##N_2## counts. Then I need to build the function ##A = \frac{N_1-N_2}{N_1+N_2}##. I am trying to estimate the...
  14. K

    A Confused about magnitude of error

    Hello! I am trying to simulate the following experiment. It is a counting experiment where the probability of getting an event after a given trial is given by: $$P = 2\left(\frac{a}{x}+\frac{b}{c}\right)^2\left(1-\cos\left(\frac{\pi x}{x_0}\right)\right)$$ where, ##a = 4\pi##, ##b = 2000\pi##...
  15. M

    C/C++ Variable defined in scope gives error depending on scope

    Hi PF! The following runs if lines 5 and 11 are commented, but fails otherwise. Can someone explain what's happening here? Something with scope but I'm very lost. Thanks in advance! #include <iostream> int main() { { int* i = new int; { int b = 5; i...
  16. A

    Basic FMESH question: "Jmesh keyword missing error"

    Can someone give me a brief explanation what are imesh jmesh kmesh values are? edit: MCNP manual says IMESH is "Locations of the coarse mesh points in the y direction for rectangular geometry or in the x direction for cylindrical geometry" Which doesnt make any sense to me... what even is...
  17. Ranger Mike

    Cosine Error: 5mm Ball Tip Stylus at 7.5° Angle

    Cosine error of a measured point on the surface is not a simple value, but a vector. If the ball contacts the part surface at a point located a distance from the theoretical or nominal point then the angle between the probe and the normal vector gets larger, P1 P2 will increase. We have cosine...
  18. B

    Python UnimplementedError: Cast string to float is not supported

    Hello everyone, I have this problem that I can't solve: I have two types of images contained in two different folders. I have to create a dataset with these images and train a cycleGAN model, but for simplicity we assume that I want to print them on monitor and forget the cycleGAN. My code is...
  19. AtoMick-u235

    Why does a division by zero produce an error or undefined message?

    A division by zero is a mathematical oddity, , if a computer or calculator etc performs a 1\0 they would crash, the OS prevents the execution, and displays ERROR or UNDEFINED, , , some versions of windows calculator display positive or negative infinity, , try it Any ideas on this ?
  20. emilmammadzada

    I get this error when I try to run the code MCNPX

    I get this error"bad trouble in imcn in routine pass1 unexpected eof in file depletion.inp" when I try to run the code MCNPX my input file c Depletion pincell input file for MCNPX c Define cells c Cell 1: Fuel 1 0 -1.0 -4 -5 -6 c Cell 2: Cladding 2 0 -2.0 4 -7 c Cell 3: Moderator 3 0 -3.0...
  21. emilmammadzada

    FRENSIE installing and compiling error

    When i want compiling to Frensie code , app gave me this error emil@DESKTOP-:~/FRENSIE-pub/build$ cmake .. -- The C compiler identification is GNU 11.3.0 -- The CXX compiler identification is GNU 11.3.0 -- The Fortran compiler identification is GNU 11.3.0 -- Detecting C compiler ABI info --...
  22. M

    C/C++ Where is the Employee.cpp file located in the code?

    I have the following two files stored in the folder "impl" on my Desktop, the CLion IDE and am running on a mac: main.cpp: #include <iostream> #include "Employee.h" int main() { Employee e1("Bradly", "E007"); Employee e2("John", "E425"); std::cout << e1.getName() << ": " <<...
  23. Suxil_7

    Java When I press the "show" button it does not show any table and error

    I need help. When I press show button it does not show any table and error. Here is the code: package Demo; import java.awt.EventQueue; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.border.EmptyBorder; import javax.swing.table.DefaultTableModel; import...
  24. P

    I Disproving Carnot's Theorem: Is There an Error in My Thinking?

    But if I would assume that the efficiency of the carnot's engine is greater than the other engine and the carnot engine is driving the other engine backward as a refrigerator ,that would lead to the same contradiction hence disproving carbot's theorem! Is there something wrong I have done...
  25. ramana3797

    BURAI quantum espresso GUI error

    I am using BURAI for quantum espresso calculations and am getting the error ATOMIC_POSITION nonexistent. I have attached the scf .in file and the crash file. I am using the CIF file of LaFeO3 I downloaded from materials project. Any help would be appreciated as I am not very familiar with these...
  26. emilmammadzada

    How to Fix OpenMc Installing Error in Terminal?

    When I run the >>mamba search openmc : command in the terminal, it gives an error. The error output is as in the picture ::Loading channell /killed. How can I solve this problem?
  27. Artemisa

    Error floors in this Bayesian analysis

    In this article((https://arxiv.org/pdf/2001.04581.pdf)), the authors use a Bayesian analysis based on the positions of astrophysical bodies and their errors in the medians. This statistical analysis uses the markov chain monte carlo chains. The uncertainties in the positions are large, so what...
  28. M

    Silvaco: "simulator has unexpectedly exited with status -1073741819"

    Hello, I am simulating the process of NMOS construction. as you know, in order to make the LDD, we need two implantations, one before creating oxide spacer and another after creating oxide spacer. at the last implantation, I am facing an error which is shown in the following image: I put...
  29. PeterDonis

    I Physics Error in Larry Niven's "Neutron Star

    In the short story "Neutron Star" by Larry Niven, the narrator, Beowulf Shaeffer, is piloting a spaceship on a hyperbolic orbit that is supposed to make a close approach to a neutron star. He says at one point that he sees incoming light from distant stars blueshifted in all directions, and...
  30. TheMercury79

    Error propagation leads to different uncertainties, which do I choose?

    I understand how to compute and propagate errors but have trouble with conceptualizing all things put together. I have performed an experiment to determine a value for some quantity. This quantity depend on two variables. The first one depend in turn on some other quantities as well but I think...
  31. Lotto

    B How to calculate measurement error by using other quantities?

    Let's say I have ##F=mg \tan \alpha## and want to calculate ##F##. I know ##m=(1.0 \pm 0.5)\,\mathrm{kg}## and ##\alpha=(20.5 \pm 0.5)° ##. How to calculate ##F=( 3.7 \pm ?)\,\mathrm N##? What is the general method of determining a measurement error in these cases?
  32. red65

    B Where is the error in my reasoning about palindromes?

    Hello everyone, I found this problem online about probability, for me, I think that to have a 2 letter palindrome is less likely because we need to have the same letter in the 2 places which gives us 26 possibilities (aa , bb, cc ....) however for words with 3 letters we have 26 possibilities...
  33. E

    I Error Propagation in Measurements

    I was imagining trying to construct a rectangle of area ##A = xy## If we give a symmetric error to each dimension ##\epsilon_x, \epsilon_y## $$ A + \Delta A = ( x \pm \epsilon_x )( y \pm \epsilon_y )$$ Expanding the RHS and dividing through by ##A## $$ \frac{\Delta A}{ A} = \pm...
  34. emilmammadzada

    Fixing MCNPX Fatal Error: Too Many Numbers First Entry

    When I run the application, I get an error message. This message: Fatal error too many numbers first entry. What could be the reason?
  35. ramana3797

    Quantum Espresso make all error

    The system at my college died and I did a fresh install of ubuntu and tried to install quantum espresso after installing the required dependancies according to the instructions in the link "https://osuginoissp.wixsite.com/mysite/a-install-quantum-espresso" . But the make all command keeps...
  36. C

    The percentage error in the Radioactive substance Population

    Please check the question below as given originally. Answer given is 25%. I am unable to proceed. It is given that the half-life is underestimated by 10% therefore it must be larger than originally estimated. What I can find using the percentage error formula is ##\left(...
  37. Lotto

    B How to calculate a random measurement error?

    I have seen this formula $$\sigma=\sqrt{\frac {\sum_{i=1}^{N}{(X_i- \bar{X})^2}}{N(N-1)}}$$ but also this formula $$\sigma =\frac{\sum_{i=1}^{N}{|X_i- \bar {X}|}}{N}.$$ Which of them is correct?
  38. A

    Uncertainty of the Standard Deviation

    Using this error propagation formula: I expressed the standard deviation (s) and the partial derivatives of s w.r.t. each data point as: This gives me an uncertainty of: , where m is the mean. Does this seem reasonable for the uncertainty of the standard deviation? I also found the thread...
  39. P

    I Error of the WKB approximation

    hello everyone I tell you a little about my situation. I already found the approximate wavefunctions for the schrodinger equation with the potential ##V(x) = x^2##, likewise, energy, etc. I have the approximate WKB solution and also the exact numeric solution. What I need to do is to calculate...
  40. S

    B Error in approximation to log(223)/log(3) .... senior moment?

    This is probably a silly question, but I am really stuck. A possible senior moment, is my only excuse. Here is an approximation: ##log(223)/log(3) \approx 10818288 / 2198026 ## So we have: ##log(223)/log(3) - 10818288 / 2198026 = 0.0399292## which is OK but not great -- the error shows up...
  41. K

    A Error signal when locking a cavity

    Hello! I am trying to lock a laser to a bow-tie cavity. I managed to align the cavity to a certain degree but when I lock it, the error signal looks as below. I do get a significant power enhancement (although about 10 times smaller than expected) and the lock is relatively stable, but the error...
  42. M

    React - load new image - error - part 2

    It works with this code! If I want to write a text next to the image do I use <div> ? I mean : return <div><div><img src={logo} alt="Logo" width="40" /></div><div>Title</div></div>; 🤔
  43. M

    React - load new image - error

    Hey! :smile: I need some help in react. I have a code for a web application and I want to change the logo. The logo I want to use is in the public folder, in this folder there is also a favicon with the old image. In the src folder there is a folder images with the old image. In the src folder...
  44. V

    Comp Sci Finding Optimal h for Truncation Error O(h2)

    Part (A) I have already determined the truncation error of order O(h2). Part (B) I'm struggling with how to approach this part. I do not really understand where to begin to figure out what value of h is the approximation the smallest. Is this looking for a particular range? Or are we isolating...
  45. M

    I Error propagation and symmetric errors

    Hello! I am a bit confused about how to interpret symmetric error when doing error propagation. For example, if I have ##E = \frac{mv^2}{2}##, and I do error propagation I get ##\frac{dE}{E} = 2\frac{dv}{v}##. Which implies that if I have v being normally distributed, and hence having a...
  46. V

    Least count error Vs Least count

    I know that least count is the smallest measurement that is possible with a measuring device. But I fail to understand the exact meaning of least count error. According to my textbook, the following is the definition of least count error. "Least count error is the error associated with the...
  47. M

    Python Any help with this error in Scipy minimize function?

    Hi PF! When I execute the code below: import numpy as np from scipy.stats import t import scipy.optimize as optimizeglobal data data = np.random.normal(loc=50, scale=1, size=(2400, 1)).flatten() def L(F): M = 250 lmda = 0.97 sig_0 = F[0] for i in range(1, 12): sig_0 +=...
  48. ramana3797

    I need help to fix a Quantum Espresso installation error in Linux

    I'm a M.Sc physics student and I need to use quantum espresso for my research project . I tried the same procedure I used to install it on the system at home as I did for the one at the College but i keep getting the same error . I can't find why . I'm also new to linux . I'm using ubuntu and I...