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. M

    Calculate Probability Error for 100 Exp: Sample Size of 15

    I have a sample size of 100 experiments out of which 15 are unfavorable events. I do this measurement for different initial conditions of my experiment. The sample size remains constant but the no. of unfavorable events change in each case. I calculate the probability of success in each case...
  2. S

    What is the Error Source in SHM Experiment with Floating Cylinder?

    Homework Statement Investigating the effect of mass on the period of oscillation. This experiment is about SHM of a floating cylinder, and the theory is explained in this website: http://physics.stackexchange.com/questions/64154/shm-of-floating-objects Also, I'm attaching a diagram of my...
  3. T

    Quantifying Observational Error in FWHM Measurements of Optical Signals

    Hello, i have a optical signal(x is length in pixels and y is amplitude ) and i have found a number of FWHM values of peaks. The width is measured in pixels, let's say the average width of 50 peaks is 8,7 pixels, standard deviation is 0,6 and the average amplitude of peaks is 38 and standard...
  4. Schwarzschild90

    Identifying Error in Spherical Coordinates - Homework Problem

    Homework Statement Homework Equations And the volume element dV expressed in spherical coordinates. The Attempt at a Solution Can you spot where I've made an error?
  5. M

    Simulation error messages solidworks - invalid goals

    I am running a simulation on a flat plate heat exchanger and the solver is coming up with some error messages. The first says that a vortex crosses the pressure opening and the second says that my heat transfer rate goals are invalid. How can I get the heat transfer goals to be valid as I need...
  6. X

    Error in angular magnification calculation

    Homework Statement The wing of an insect is 1.7 mm long. When viewed through a microscope, the image is 1.4 m long and is located 5.9 m away. Determine the angular magnification. Homework Equations di/do=hi/ho M=beta/alpha alpha=object size/object distance beta=image size/image distance The...
  7. I

    Error propagation - partial derivative?

    I am getting a little confused on which error propagation to use: I am looking to calculate the error in B*Cos(θ) , for the vertical axis of a williamson hall plot. where B is fwhm of a peak with it's own error and cos of the bragg angle I am unsure of whether i need to use partial derivative...
  8. Y

    Receive a certificate error in Internet Exp 11

    I use Internet Explorer to get into my sbcglobal.net email. It has been working fine all these years. All of a sudden, my desktop gives me Certificate error when I click the "Mail" in Yahoo page. The message is: Security certificate presented by the website has expired or not yet valid...
  9. A

    Python How to continue this Python program?

    Homework Statement I need a program where the program needs to ask me a name of a student and then a grade. 1) The program needs to end if a 0 is entered. 2) If the name has a number in it, the program should ask the user to enter another name. 3) After the name is correctly entered the program...
  10. LeoDimieri

    Mathematica Solving ODE numerically in Mathematica - I get 'ndnum' error

    Hello everyone! I'm trying hard to solve numerically a system of coupled differential equations of first order, but I get this error everytime.. I can't find the reason.. maybe you can help me, I'd really apreciate that. This is the code: Jg=0.000043; Kg=0.5; Bg=0.06; Bpm=0.5; r=0.11...
  11. S

    Issue Finding the Mean Squared Error / Polyfit MATLAB

    Homework Statement Homework Equations Given above The Attempt at a Solution I used polyfit, but my mean swuare errors are way bigger than they should be- don't see what is wrong with my code! My code is ugly btw, my apologies. %Hw 7 clear all close all y3=[1960; 1965; 1970; 1975; 1980...
  12. J

    How Do You Calculate Overall Error Percentage Between Two Data Sets?

    Hi, I have 3 values for data set 1 (1a, 1b, 1c), and 3 values for data set 2 (2a, 2b, 2c). (assume set 1 are the ones being compared to) I know that to work out the error percentage for 1a and 2a -- it is the difference (of 1a and 2a) divided by 1a x 100. I can do the same with 1b and 2b, and...
  13. T

    Questions about the error in the slope of a graph

    Homework Statement I am doing a lab report and I have to find the slope of a graph as well as the max and min lines of the graph. I also have to find the error in the slope. I have calculated the slope. My first problem is in calculating the error lines. My teacher said i must find the slope...
  14. S

    VHDL Newbie Stumped by Error 10380

    I'm super confused on why I keep getting an error on this code. I feel like I've tried everything but now I've run into mental block lol. My error message is: Error (10380): VHDL error at lab2.vhd(6): std_logic type is used but not declared as an array type Here is the code I came up with...
  15. Antonija

    Comp Sci Fortran error *** glibc detected ***

    Homework Statement I'm doing aproximation of derivative called five-point stencil. For every value of x, in interval [a,b], in step of 0.1 i need to calculate derivative.Homework Equations [/B] The equation is like this: Five-point stencil: (-f(x + 2h) + 8f(x + h) - 8f(x - h) + f(x -...
  16. evinda

    MHB Euler's Method Error: Linear Functions

    Hello! (Smile) Theorem: Let $f \in C([a,b] \times \mathbb{R})$ function that satifies the total Lipschitz condition and let $y \in C^2([a,b])$ the solution of the ODE $\left\{\begin{matrix} y=f(t,y(t)) &, a \leq t \leq b \\ y(a)=y_0 & \end{matrix}\right.$ If $y^0, y^1, \dots, y^N$ are the...
  17. A

    Propagation of error: exponents

    Hi all. I have been trying to understand propagation of error of exponents. Most an. Chem textbooks I see say y = a^x, sy/y = (sa/a)*x. But say y = a*b, then sy/y = ((sa/a)^2 + (sb/b)^2)^.5 . if a = b then sy/y= (2*(sa/a)^2)^.5 = 2^.5*abs(sa/a). This shows the rule y=a^x, sy/y= x^.5*abs(sa/a).
  18. S

    Error Analysis of Modern Gram Schmidt Technique -code bug

    Hi all, I am to compute A = QR using the Modified Gram-Schmidt algorithm. I need to find the error using the one norm of : (Q transpose * Q) - I. Here is my code: %Modern Gram Schmidt p=zeros(5,5); e=zeros(5,5); g=zeros(5,5); for k=1:n; p(:,k)=(A(:,k)); end %j=k, i=u, r=g, q=e, v=p for...
  19. Aileen Gordola

    Error in Calculation of EDissolution?

    I calculated the Edissolution of a reaction and resulted in a negative number. However, during the wet lab the reaction was clearly endothermic since there was a drop in temperature. I used the equation: ∆Edissolution = Ccup∆Tcup/mass of salt What is the reason for the negative number? Would i...
  20. F

    Error propagation for a sum of means

    I have a = {a1, a2, .., a1000}, where this set forms a distribution of photoelectrons (pe) seen by a particular photomultiplier tube (pmt) over 1000 repeated events. I then have N sets of these (N pmts), each containing 1000 pe values which I believe are indeed random and independent. So a, b...
  21. S

    Troubleshooting Transformer Core Loss Simulation Error

    Hello Engineers, while simulating transformer core losses in transient Maxwell sollution, I have got an error: Current leak to the air. does anyone ahev idea to solve this problem Thank you
  22. S

    How Do You Properly Round in Error Analysis?

    Hi, to start with my questions I will show you what I have done so far. (23.56+/-0.05) km/h x (56.3+/-0.4) h So I ended up with (1326.428+/-12.234) km But I know the real answer is (1330+/-10) km What I don't understand is how I would round to that answer. I do not know what I have to look...
  23. B

    Can You Help Me Fix this Matlab Error in My Code?

    Homework Statement Hello, i have a MATLAB code that simply lists a bunch of parameters with values and an equation that relates all of them together. I am getting on error that says Error in ==> randelltest at 17 Ys0=Yl*{(Pm-Pc)*Yc/Yl*(1-Av*Tm/2*Yc/Yl)-Av*Tm*Pm/2}*(1-1/B); Is there a problem...
  24. A

    Help Needed: Calculating Wavefront Error from PV Measurement

    Thank you all for any help or advice you can give. 1. Homework Statement What is the fabrication Wavefront error (WFE) of a mirror with a PV surface error of 1 um? Express your answer in terms of RMS waves at lambda = 0.633 um Homework Equations WFE=2*SFE The Attempt at a Solution I know...
  25. P

    Error Propagation: Dividing By 20 in Pendulum Timing

    Homework Statement suppose i measure the time t for 20 oscillations fro a pendulum. the period is T. Homework Equations Since T = t / 20 delta T = delta t right? The Attempt at a Solution since the 20 is a numerical value, it does not come in the error propagation, does not? when i used the...
  26. 5

    Error Propagation for Tube Volume

    Homework Statement You have a cylindrical tube for which you know the length is 16±0.1 cm and the radius is 8±0.1 cm, what is the error of the volume? Homework Equations The Attempt at a Solution V = π*82*16 = 3216.99 cm But since the r term is squared, must we account for its error twice...
  27. P

    Maxwell 3D Analysis error -- please somebody help with the error

    hi dear friends i face with this error in Maxwell 3d analysis please help me Surface recovery failure. Possible reasons: (1). Model has multiple objects with thin layers. (2). Complex model with object overlapping. (3). True surfaces are skewed what should i do?
  28. D

    Error bars, Chi square distribution

    Hi, I'm doing a fit using Chi-square distribution. I have a data set and their errors, I found the best estimate minimizing Chi square, as usual, and I like to found the error bars of my best estimates but I don't know how to do that. Which is the standard form to do it?
  29. STEMucator

    Can't see the error in the transfer function

    Homework Statement Here is the problem: Homework EquationsThe Attempt at a Solution Okay so I was REALLY confused as to why something wrong happened. Here is my work for the whole question: Sorry for the terrible writing. Okay so for part a), I derived the transfer function as...
  30. S

    Error propagation for non-normal errors

    I have several measurements taken over a time series. Each data point has a standard error value. I need to sum up the data points, and determine the error associated with that sum. The error values across the time series are non-normal, so I'm assuming that I can't use the usual error...
  31. SnakeDoc

    Slight Computation Error? Not sure what I'm doing wrong

    Homework Statement Water is poured into a container that has a leak. The mass m of the water is given as a function of time t by m = 4.9t.8 - 3.0t + 21, with t ≥ 0, m in grams, and t in seconds.(a) At what time is the water mass greatest, and (b) what is that greatest mass? What is the rate of...
  32. L

    Error on biological assay results

    Hi everyone, I have a question about the error on certain biological results. Apologies for the long explanation, but it's not a trivial thing (at least, it isn't for me). This is what happens: 1. biologists take N solutions of a molecule at different concentrations (say from 10-10 to 10-5...
  33. N

    How can ISO 11929 norm help combine Poisson errors in low counting statistics?

    I have low counting stats and need to subtract background, account for efficiency, and divide by volume. How do I combine the asymmetrical (Poisson) errors?
  34. H

    Error on regression line slope

    I'm currently trying to determine the error on the slope of a regression line and the y-intercept. My y values are: My y error is: My x values are: 27.44535013 0.03928063 136 29.78207524 0.07836946 44 27.4482858 0.0385213 143 27.27481069...
  35. S

    Problem with spice -- Noise analysis error

    I am using a circuit attached as image and the AC analysis is working perfectly. Output is at the netlist of the AD8139 pin 5. The noise analysis showing the error : *Analysis directives: .AC DEC 10 10 1g .NOISE V19 V[N08184] 30 -------$ ERROR(ORPSIM-16291): Must be independent source (I or V)...
  36. M

    How did error analysis evolve over time?

    Hello, all, I am wondering if anyone can provide me information on the historical origin of error analysis; that is, with the quantification and mathematical manipulation of uncertainties in measurement. I find that all the textbooks I have stumbled upon provide a narrative of physical...
  37. S

    Divide by Zero Error: Solving Pendulum Radius

    I have data from a pendulum and I am using it to work out the radius of the pendulum. I have acceleration in the x and y directions and so thought this would be easy enough. Simply I determine the (velocity in the x direction)^2/acceleration in the y direction. However when I use python to give...
  38. Randall

    Using simpsons rule, how to find the error bound?

    Homework Statement Find the error bound using Simpsons Rule for integral of SQRT (x) dx from 1 to 9.[/B]Homework Equations E = (M * (b-a)^5) / (180 * n^4), where M = max value of the 4th deriv of x dx [/B]The Attempt at a Solution see attached please - I can't figure out what to use for the...
  39. A

    Possible sources of error/uncertainty in bifilar pendulum?

    in my AH physics investigation - measuring acceleration due to gravity, I used the bifilar suspension pendulum btw a light gate was used for the errors/problems section so far I have problems in making the rod level and keeping the two strings parallel, also all the random, calibration and...
  40. A

    Possible sources of error in compound pendulum experiment?

    completing my advanced higher physics investigation - measuring acceleration due to gravity for the oscillating mass on a spring experiment so far I have included friction between the nail & oscillating rod as a possible source of error can anyone think of anything else? thank you very much...
  41. SalfordPhysics

    How is the error in the gradient calculated?

    Homework Statement A series of 5 measurements of Y are recorded with increasing X. (i.e. gradient has units Y/X) The error in measurement of Y is ±0.05 The error in measurement of X is ±0.005. How is the error in the gradient calculated? Homework Equations - measurements[/B] Y | X...
  42. ChrisVer

    Inverse Efficiency Matrix (error)

    Hi, let's say in some experiment with ##Z^0## (eg LEP) you are able to determine the "misidentification" of your particles. Then you can find the efficiency matrix ##M_{eff}## which is given (for ##Z^0## decays to leptons or hadrons): \begin{pmatrix} N_e \\ N_\mu \\ N_\tau \\ N_{had}...
  43. G

    Calculating Rth Error: Different Answers for Finding Rth | Physics Homework Help

    Homework Statement Hi Guys, I am doing a number of questions on finding Rth and can across this example. When I looked at the answers I had a different one to them but I actually think they may be wrong. Could you guys please take a look? Homework EquationsThe Attempt at a Solution So they...
  44. K

    Is the Maclaurin Expansion Valid for Infinite Points?

    my professor told me any n times differentiable function can be approximated by macularine/taylor expansion.is that true? As far as I know, if the function is approximated at point a, the approximation is valid if we pick a point near a. however, if we assume that we picked a point of...
  45. L

    Utilize the Trapezoid Rule for e^cosx, and find the error

    Homework Statement Consider the definite integral, from 0 to 4, e^(cosx) dx a) Compute the estimate for this integral using the trapezoid rule with n = 4. b) Find a bound for the error in part a. c) How large should n be to guarantee that the size of the error in using Tn is less than 0.0001...
  46. D

    Why Is My MATLAB Steady State Error Different from Manual Calculation?

    I am trying to calculate the steady state error of the following system but unable to do it. I have used MATLAB and calculated the steady state error to be 0.1128 but don't understand the steps that I need to do to calculate this. Please help. Thanks
  47. J

    How to calculate error propagation for several measurements?

    I'm having trouble with error propagation analysis. When you make a single measurement of several variables, say (x,y,z) and you calculate a function f(x,y,z), you just have to apply the common formula of error propagation: $$\sigma_f(x,y,z)=\sqrt{\left| \frac{\partial f}{\partial x} \right|...
  48. A

    MATLAB [MATLAB] I am getting this error, could anyone solve it please?

    [MATLAB] The cod is: function RunLogOscilNumeric3 k =10; p0 =0.001; t = [0:0.01:10000 ]; omega = 1; N0 = 1; options =[ 'AbsTol',1e-3,'RelTol',1e-6] % options =odeset(...
  49. STEMucator

    Find and Plot v_o(t) in Solution: Homework Equations & Attempt at a Solution

    Homework Statement Find ##v_o(t)## and plot it. Homework EquationsThe Attempt at a Solution The solution was provided, and I got all of the same numbers except for one thing. For some reason, in step 3 there is a negative sign in front of ##v_c(t = 0^+)## when calculating ##v_o(t = 0^+)##...
  50. D

    What is the error analysis for a function of Newton's cooling law?

    Hi guys, I have a silly question, but I seem to be confused about it. Let's say I have a function of Newton's cooling law. I measured the exponential drop of the temperature of some system and now I want to make an error analysis. Do I treat this function as a two variable function of tau (time...
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