Error Definition and 998 Threads

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. dwdoyle8854

    Does Object Size Affect Measurement Errors?

    Homework Statement "Which will have a larger absolute measurement error, a larger object or a smaller object?" "Which will have a larger relative measurement error, a larger object or a smaller object?" Homework Equations Relative error: δ(A)/A = δ(B)/B + δ(C)/C The Attempt at a...
  2. Q

    Electric Force Textbook error?

    Homework Statement Find the net force given a point charge and the value of the electric field. Homework Equations FE = εq ε= (5.6*10^4) q=(-1.2 * 10^-5) The Attempt at a Solution FE = εq FE = (5.6*10^4)(-1.2 * 10^-5) FE = 0.672 N [left] Seriously. I am posting this...
  3. P

    MATLAB MATLAB ezplot Error: Get Help Here!

    Hi. I was writing the simplest code ever in Matlab when I got an error using the ezplot function. I wrote this script: syms z t; eq=2600*tan(z)-0.5*9.81*2600^2*(210*cos(z))^(-2)-350; theta=solve(eq, 'Real', true); x=210*cos(theta); y=210*sin(theta)*t-0.5*9.81*t^2...
  4. A

    R through a wire: What's the max error in diameter if your R has 1% uncertainty?

    Homework Statement I have a wire of some resistance, resistivity, and length. What is the maximum error in measuring the diameter that you can have if the resistance is to have 1% uncertainty? Homework Equations R = \frac{ρ*l}{\pi*r^{2}} for which I substituted the area as \pi(.5...
  5. J

    Quantifying the statistical error in a counting experiment

    I need to find the statistical error in a counting experiment. Specifically, a decay can proceed via option A or option B and I need to find the branching ratio BR_a=(N_a)/(N_a+N_b). If I were to do this counting experiment multiple times my results for BR_a would follow the binomial...
  6. J

    What is the Standard Deviation of the Mean for Lab Homework Data?

    Homework Statement Using 5 different ammeters, you get the following data (all measured in Amps): I_{A} = 128 ± 2 I_{B} = 121 ± 1 I_{C} = 114 ± 8 I_{D} = 120 ± 3 I_{E} = 122 ± 4 Calculate the mean current and the standard deviation of the mean. Homework Equations Standard...
  7. T

    How to find the error in this particular integration process?

    Homework Statement The problem, more like a riddle, that our teacher gave it to us was to find the error in this particular equation: integral of 1/x dc = ln (absolute value of (x)) + C ; perfectly fine integral of dx/3x = 1/3 integral of dx/x ; also fine 1/3 integral dx/x = 1/3 ln...
  8. N

    MHB Logical error in Spivak's Calculus?

    Yes I am another plucky young fool who decided to self study Spivak. I think I have found an error in his section on conic sections, but Spivak is seldom wrong and I want to be sure I'm thinking straight. Let $C$ be a cone generated by a line of gradient $m$ which goes through the origin. Then...
  9. I

    Calculating Error in Multiple Independent Variables

    Homework Statement Okay so I was given this question to start calculating error on other problems. Consider the equation F(x,y,z) = x^4+2y^3+5yz+5. Let the uncertainty in x be represented by the variable dx, the uncertainty in y be represented by the variable dy, and the uncertainty in z...
  10. N

    Solving "Fatal Error" in MCNPX Input Code

    I am running a simple MCNPX input code and am getting a fatal error that says: "Fatal Error: no m card for material no. X". I thought it was something with my data card or my cell cards but can not figure out what the problem is.
  11. H

    Fortran Array reading error when opening multiple files in Fortran

    Guys. I really need help. I have been working in this little problem for hours. I had a problem in array reading when I opened more than 1 files, it seems like an array with different names mixed each other. Here is my code integer, parameter::size=11 real, dimension(101) :: cldata...
  12. B

    How to Evaluate Model Performance for Simulated Power Demand?

    How to quantify performance of a model Hello, I was hoping that somebody could advise me how to do evaluate the performance of a model. The model simulates the power demand from a fleet of electric cars over 24 hours. For example take the blue line as the actual demand for a given day and...
  13. Fb.Researcher

    Segmentation fault (core dumped) C error for structures

    I have written a C program that produce a structure, give it's elements their initial values and change these values when neccessary.I can compile my program but when I try to run it,error:"segmentation fault(core dumped)" appears.I commented different parts of my program and I underentood the...
  14. N

    Error: Bad Trouble in IMCN - Unexpected EOF

    I am getting an error which reads as follows: "bad trouble in imcn in routine pass1 unexpected eof in file ****** " I just added a sdef and nps card to my input file, so I assumed the error was with one of those. SDEF AXS=0 0 1 ERG=D1 RAD=D2 WGT=1 TME=0 PAR=1 SI1 0 .4...
  15. M

    Why do binary arithmetic operations sometimes result in different outputs?

    Hello everyone ! I got a problem, I can't figure out why when I compute A+B and 2\times (\frac{A}{2}+\frac{B}{2}) the result is sometimes different. Can anyone explain why the results of the two operations are different ? Edit : A and B are coded in binary of course and we compute a binary...
  16. P

    Data analysis: error calculation

    Homework Statement A=0,078m l=2,27m relative error of A: 0,01 relative error of l: 0,005 What is the error of: arctan(A/l)?
  17. Duderonimous

    Error propagation of q=mcdeltat

    Homework Statement I want to know how to do error propagation on this cNi= [-(mcΔt)Al-(mcΔt)H2O]/(mΔt)Ni m is mass and Δt is change in temperature Homework Equations δc/c=√(δm/m)2+(δ(Δt)/Δt)2 The Attempt at a Solution I know the above error prop eq. above applies to c=Q/mΔt...
  18. T

    Python Python: Old-style to New-style Class Conversion Causes Error

    I'm trying to convert my __init__ to __new__, but I can't find any docs on how the syntax differs or anything really, that pertains to how this bug could be caused by it. What am I doing wrong here? import copy; class grid(list): def __new__(self, size): self.size = size...
  19. U

    Third kepler's law error on sun mass calculation

    Homework Statement We consider that at the third Kepler's law the Earth mass is 0, that way we are making an error at the Sun mass calculation in comparison to the real Sun mass. In the same calculation we make another error by taking the common error at the gravitational constant, G. Which...
  20. F

    Propagation of Errors - Error on Gradient

    Homework Statement So I'm trying to calculate the error on the gradient I've obtained for my lab work. The line of best fit is too precise to use the parallelogram method and I'm still at the stage of my course where calculations of the gradient and such must be done by hand and not using a...
  21. M

    Error by a factor of 10 in peroxide/permanganate titration

    Hi all, Trying to get this titration working correctly and for the life of me, I can't figure out where my error is. This is what I have: Burette contains 0.01M KMnO4 (I'm positive that my error does not come from preparing this - 0.4g in 250ml of water, with a molar mass of 158g/mol...
  22. O

    Estimating Error in Meas. of Homog. Mag Field w/ Hall Effect Probe

    Homework Statement I'm trying to estimate the error in measurements of a homogenous magnetic field of known orientation using a Gauss-meter that uses a Hall-effect probe. The uncertainty in the measurements reported by the Gauss-meter are given the user's manual. Since the probe is held by...
  23. 0

    Error Propagation: Calc Errors w/ Variance Covariance Matrix

    I am confused about calculating errors. I have learned if you take the variance covariance matrix \Sigma_{ij} of a fit of function f(x,p) to data for parameters p_i (for example by using Levenberg-Marquart) that the one sigma error interval for p_i is \sigma_{p_i}=\sqrt{\Sigma_{ii}} I only...
  24. B

    How to Calculate Error on Beat Frequency?

    I'm being asked to calculate the error on a beat frequency. The beat frequency was found to be 1/20.0s The equation given is The thing is I am not really sure where to go from there or how to get the derivative of that, any help or pointing me in the right direction would be...
  25. S

    Proportional Controller and SS Error

    hi i am having a bit of a problem understanding the steady state error in proportional controllers.. The output from a P type Controller is proportional (u=kp(error))to the error so why does this error arise?? The output from the controller tries to achieve the S.P. Once the O/p = SP the...
  26. baby_1

    Engineering What Does A=0 or S=-3/2 Indicate in Laplace Transform Analysis?

    Laplace Error in a Circuit ! Hello as you see this circuit i want to find the v(t) across the 2ohm resistor.(VC(0-)=0) i assume A node above the capacitor , so we have (in Laplace) so i have so A=0 ! or S=-3/2 ! what can we understand about A=0 or S=-3/2 ? what is their inverse...
  27. A

    Fortran Dealing with IMPLICIT Definitions and Variable Type Errors in FORTRAN Code?

    So I have been trying to write a code which calls from REFPROP subroutines to get thermodynamic properties and then uses these to do some other calculations. I am facing two issues: 1) The REFPROP subroutines require IMPLICIT definitions so I can't say IMPLICIT none at the top, and this may...
  28. P

    C/C++ Microsoft Visual Studio C++ error

    Hello, I'm new to Microsoft Visual Studio and new to the C++ program. I just installed the program and I'm trying to write my first program. First error that I get is: ========== Build: 0 succeeded, 0 failed, 1 up-to-date, 0 skipped ========== Why is my project out-of-date? Second...
  29. B

    Fluids - maximum error - diameters

    1. Homework Statement : The expressions you obtained for acceleration and drainage time (equations 3 and 4 in the manual) both contain the following factor or something equivalent: (D/d)^4-1 In the lab, we will be dealing with a bottle with a diameter around 9 cm. A typical diameter of the...
  30. W

    Taylor series error term - graphical representation

    Hello all, Recently I've found something very interesting concerning Taylor series. It's a graphical representation of a second order error bound of the series. Here is the link: http://www.karlscalculus.org/l8_4-1.html My question is: is it possible to represent higher order error bounds...
  31. S

    Relative Error Propogation in Equations

    Greetings, In atomic spectra experiment I came across with error propogation in the nonlinear equation: \lambda=d\times\sin(\theta) which gives the wavelength when first order constructive interference is observed at a given angle with respect to the normal of the plane of the grating. The...
  32. E

    Error in defined expression for Fresnel equation in matlab ( please )?

    error in defined expression for Fresnel equation in MATLAB (urgent please )?? hi i have code for plotting Fresnel equation but there's something i didn't understand it and gives error >>((( plotopt - plotting option (type 'R' for plotting reflectivity, % 'A' for absorptivity or 'RA'...
  33. A

    Sampling Error, Homogenous Mixture, Heterogenous Mixture: Benefits/Drawbacks

    Why do you have to use a homogenous mixture in an experiment what are the disadvantages of using a heterogenous mixture?
  34. S

    Friction problem- possible error in Halliday/Resnick

    Homework Statement See attachment. I am only concerned with part b). Part a) is solved. Homework Equations The Attempt at a Solution See attachment. The solution is quoted to be tan-1(μs) = θ0, but, as can be seen by my solution, this is impossible based on the derivation. Is...
  35. O

    Is my book making an algebra error?

    Not sure if this is a notation error or an algebra or if I am wrong , but my book presents a system of equations and I cannot get it into the form which it is presented \tau _b = \left(1 + \frac{\Phi _b}{c^2}\right)\text{ }\text{$\Delta $t} \tau _a = \left(1 + \frac{\Phi _a}{c^2}\right)\text{...
  36. J

    Error analysis of acousto-optic effect

    Homework Statement Hey guys, I have recently done an experiment in regards to the acousto-optic effect (which in itself is freaking amazing!). And i need to do an error analysis for my value of the phase velocity. I believe i have made a mistake but i can't find it anywhere. Firstly i have...
  37. J

    Maybe a dumb question on standard error in equations

    Homework Statement I am using a value of change in y say 12.10 cm + or - .06cm. I am trying to find velocity using the formula v= sqrt(2*g*change in y) how do I evaluate this equation with my standard error? because I can't just add or subtract the .06cm after since I will have a...
  38. D

    Mean Squared Error of an estimator.

    Hi. Let X_1 and X_2 be independent random variables with mean  μ and variance σ^2. \Theta = ( X_1 + 3X_2 ) /4 a) is it unbiased? b) what is the variance of the estimator? c) what is the mean squared error of the estimator? since there are four things, divided by 4...
  39. R

    Approximation of error function-type integral

    Hi! How do I approximate the integral \begin{equation} \int_0^{\infty} dt \:e^{-iA(t-B)^2} \end{equation} with A, B real, A > 0, and B=b \cos\theta where 0 \leq \theta < 2\pi? I guess for B\ll 0 the lower limit may be extended to - \infty to yield a full complex gaussian integral, but what...
  40. V

    The error caused by the lagrange inversion

    Hi, I have problem with the calculation the error caused by the lagrange inversion. Hence, accroding to Lagrange theorem if f(w)=z it is possible to find w=g(z) where g(z) is given by a series. I wonder, if I consider up to N-th term in the Lagrange series, what will be the error caused by...
  41. M

    Curve-fitting to data with horizontal/vertical error bars

    Hello I've measured some data, let's say f±Δf as a function of x±Δx, and I know the form of f(x) but not the specific parameters, so it will be something like f(x) = (A/x)*exp(-B/x + C), I think. I'm comfortable enough fitting the data (x,f) to the curve and finding A,B,C, but can anyone point...
  42. T

    Determining margin off error within experimental calculations

    For a physics project, a few friends and I got ahold of a couple of balls that would record the time of an impact. Using this, we wanted to calculate g using kinematics to see how off we would be from the expected 9.81 m/s^2. Obviously, differences in altitude, air resistance, and experimental...
  43. W

    Accounting For Error on Air Track, Conservation Lab

    This is a conservation of momentum/energy lab. We have an air track with motion sensors at both ends. Bumpers are staged to give elastic collisions. There are two gliders on the track. For this part the second glider remains stationary near the center of the track. The first glider is sent to...
  44. P

    Mathematica Mathematica: Help with NDSolve Error

    Mathematica: Help with NDSolve Error! Hello All, I am attempting to set up a model of an experiment I am running, but I keep getting the following error: "NDSolve::ibcinc: Warning: Boundary and initial conditions are inconsistent." However, I have checked all of my boundary...
  45. T

    Error propagation for effective spring constant

    Homework Statement Calculate the error propagation for the theoretical effective spring constant for the two springs. The actual values don't matter, it's just supposed to show how it would be calculated. Homework Equations ke=k1*k2/(k1+k2) The Attempt at a Solution ke=A*B/(A+B) (Let...
  46. O

    How do you give an error for someone entering a letter

    #include <iostream> #include <cstdlib> #include <cmath> using std::cout; using std::endl; using std::cin; double sort(double input[], int N) { double temp; int i, j; for (i=0; i<=8; i++) { for (j=i+1; j<=9; j++) { if(input[i]>input[j]) { temp=input[i]...
  47. P

    How Is Error on Half-Life Calculated Using Poisson Distribution?

    How may the error on the half life (using Poisson) be calculated? Barlow states that the error on the log would be 1/√N. Why is that?
  48. P

    Finding error on gravitational acceleration

    How may the error on gravitational acceleration (g) be determined, given a set of measurements of time (t) and distance (d)? It is stated that the distances are measured precisely and time with an accuracy of 0.01 sec. I have applied Least Squares on t = √(2/g) * √d and found (σ of √g) albeit...
  49. O

    Error of Product: Calculating Speed of Sound Formula

    I'm teaching one of the physics labs for non-science majors at my school this year, and I ran across a formula in the first lab that's confusing me. They are using an oscilloscope to measure the wavelength of sound at a given frequency in order to determine the speed of sound. The lab manual...
  50. A

    Calculating Error for Function of Fit Parameters in GNUplot

    Homework Statement Given is a set of measurements with their respective errors for example an energy spectrum. In gnuplot one is to fit a function f(x;\{p_i\}) depending on a variable x and on fit parameters p_i. When the fit is done one gets values for the p_i with errors and a correlation...
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