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. R

    Photodiode : ask help too find 10x calculation error

    Hello Can anybody help me find my mistake in the following reasoning for light falling on a photodiode : "When 0.1464 watts/m2 fall on a 7.34 mm2 window, 1.07E-06 watts will penetrate and for a 0.38 A/W photodiode will produce 4.08E-07 amps which, across a 100k resistance will produce 0.0408...
  2. ChrisVer

    What is the best method for plotting function parameter errors?

    Hi, suppose that you have some function: F(x;a) where x is the variable with which you plot the function and a is some parameter which enters the function. If I want to find the error coming from some uncertainty in a, computationally, I would have to plot the function for 2 different let's say...
  3. D

    Help Solving Physics Exam Question on Gamma Rays Counting Rate

    Hi, I came across a question in an exam which I couldn't really relate to any topic of physics, that I had studied. It goes like this- A detector is used to count the number of gamma rays emitted by a radioactive source. If the number of counts recorded in exactly 20 seconds is 10000, the...
  4. D

    Sources of Error in Youngs double slit experiment

    Homework Statement [/B] we used a laser pointer as a light source Homework Equations I'm having trouble looking for an error in the experiment. The Attempt at a Solution
  5. S

    Fortran Error 6404 when running fortran code in visual studio

    I am trying to compile several libraries of FORTRAN code and getting the error message as can be seen in the screen shot. As I do not have any experience with FORTRAN I am not sure what is wrong in the line highlighted line. Any help would be greatly appreciated! Thanks a lot! :-)
  6. J

    C/C++ Compiler error do to too much "constness" in my C++ program?

    Can someone try compiler this and tell me what error you get and what it means? https://github.com/jamkin/CSS-Template-Generator/tree/master/CSS%20Template%20Generator I get Mod note: Removed the [ I ] tags and the [ color ] BBCode tags, and replaced with [ code ] tags. There were too many...
  7. S

    Error Propagation and Uncertainties in Parameters

    There is a quantity (W) that I would like to calculate that is, ultimately, a function of parameters that I can measure directly (a and b), W = W(a, b) But I cannot measure a and b perfectly, there will be some uncertainty in these measurements. This uncertainty will propagate into my...
  8. G

    Solving the Homework Puzzle: Finding Your Error with Surface Integrals

    Homework Statement The problem is given in the attached file. Homework Equations Divergence theorem, flux / surface integral The Attempt at a Solution [/B] As you can see I got the question correct using Divergence theorem. But I wanted to make sure that I could arrive at the same answer...
  9. J

    What Causes Lower Cp/Cv Ratio in Experiments?

    Homework Statement Hello, Everyone! So I recently did an experiment in which I pressurised a vessel and then allowed some of the air to move into a smaller vessel and wait for the pressures to stabilise. I then calculated the Cp/Cv ratio and it was slightly lower than the expected 1.40. I am...
  10. Matterwave

    Fortran Why am I getting a Fortran runtime error when trying to print more values?

    Hi guys, I've been tinkering with this code for a while now, as you probably have seen from my other threads. Right now I am working on changing the code around so that it actually writes out the correct output instead of the old output. I am getting this runtime error: At line 2057 of file...
  11. M

    Error in applying Coulomb's law

    Well, it's not so much an error as it is a fundamental lack of understanding about multiplication of units greater than vs less than 1. 1. If two charges are repelling each other which have values greater than 1, then the value of q1q2 will be greater than the individual values charge values of...
  12. B

    Textbook error or am I just confused?

    The high school textbook I’m reading says this: Statement A “Many household appliances contain an electrically heated resistor. A resistor is a device that opposes the flow of current and as it does this, heat energy is produced. E.g. electric kettles, electric fires, light bulbs. If we...
  13. T

    Ti-89 Limit of Integral undefined BUT it is 4 both by hand and Mathematica

    I am giving the following input to Ti-89 Titanium: limit(S((2 x cos(100 x Pi x t)+2 x sin(10 x Pi x t))2 ,t,-t1,t1)/(2 x t1),t1,inf) where S is the integral symbol, Pi is π = 3.14, x is the multiplication symbol and inf is the infinity symbol The TI-89 answer is undef If I do it by hand it...
  14. C

    Should I Use Total or Partial Differentiation in Absolute Error Calculation?

    The absolute error of the quantity p should be calculated. p=a*b where a and b are two variables. By taking ln on both sides: lnp=lna+lnb, then differentiating: dp/p=da/a+db/b dp=abolute error Should I have used total or partial differential in the differentiation step?
  15. J

    Finding uncertainty for varying error bars

    Homework Statement I am currently doing an experiment on Compton scattering and have plotted a linear graph of 1/E' on (1-cos θ), where E' is the scattered gamma ray energy. My goal is to find the value of the gradient and y-intercept with their corresponding uncertainties. Instead of using the...
  16. M

    Sensor - accelerations to displacements, error

    Hello everybody, apologies from outset for bad English. I wonder if anyone can give me some advice regarding my problem. I have a sesnor that gives acceleration readings. I have been working hard to turn these readings into position or displacements. I tried many method but MATLAB cumptrapz...
  17. M

    Referees missed error in submitted paper

    I recently submitted a paper to a respectable journal. After submission, I discovered a few errors in my paper, one of which is quite serious. I have the corrected expressions and plots and I've checked that they are in agreement with the overall theory (as presented in other papers). My...
  18. K

    Finding the Error in z for q = -0.6 \pm 10\% and z = 0.2

    Homework Statement For the equation q = \frac{z(z+2) - 2DH}{z^2} q = -0.6 \pm 10\% , and z = 0.2. D and H are known exactly. I have to find the error in z that will give an answer of q = -0.6 \pm 10\% Homework EquationsThe Attempt at a Solution I have considered rewriting the equation...
  19. D

    Minimum mean square error for two random variables

    Homework Statement Determine the minimum mean square error for the joint PMF. You will need to evaluate ##E_{X, Y}[(Y - 14/11\cdot X - 1/11)^2]##. Homework EquationsThe Attempt at a Solution The answer is ##\frac{3}{22}##, but when I work it out, I get ##\frac{203}{484}##. From my values, I...
  20. N

    Field due to point charges - extremely strange error

    Homework Statement Find electric field anywhere on the x-axis due two two point charges Q at (0,0,d) -Q at (0,0,-d) Homework EquationsThe Attempt at a Solution AttachedSomehow I am not getting the correct answer. I reviewed my steps with 4 people and we could not find the error! I'm...
  21. D

    Flowmeter Problems: Investigating a 12l/min Difference

    Hi there, I am currently doing leak testing for a piece of equipment. In order to do so I have a flowmeter at the inlet and outlet (of what is essentially a long cylinder) and have air drawn through by a vacuum pump. Now, the problem is that even with no obvious signs of leaks the two flows...
  22. S

    Class 1 Lever Experiment: Wrong results

    Hey guys, I really need help with this, I do not understand what I did wrong in this experiment. I had a 30 cm ruler as a beam and some weights of 50 grams, 5 grams and 25 grams. I had a fulcrum which was 17 cm high. As you can see I only have measurements in 50, 5 and 25 grams. So I cut out...
  23. L

    Calculating Experimental Error of Braggs Equation

    Homework Statement I am writing a lab report for an X-ray diffraction. I have been attempting to come up with an equation for the error using formulas some people from college gave me and also some I found on wikipedia but I am quite sure I am doing it wrong. The only variable is the angle...
  24. S

    How to Calculate Error in Fourier Series and its Approximation of Angles?

    Does anyone know how to calculate the error between a function and its Fourier series representation as a function of the partial sums of the series? So far I haven't been able to find anything in the literature that talks about this. I'm also interested in looking at how well a Fourier series...
  25. L

    How Do I Calculate Experimental Error in X-ray Diffraction?

    Homework Statement I am writing a lab report for an X-ray diffraction. I have been attempting to come up with an equation for the error using formulas some people from college gave me and also some I found on wikipedia but I am quite sure I am doing it wrong. The only variable is the angle...
  26. M

    MATLAB Why Does Matlab Say Matrix Must Be Square When Using mpower?

    When running the following code on Matlab: >> y(i) = y(i-1) + (0.5 * y.^3 * exp(t^2 + t))*h I get the error: ? Error using ==> mpower Matrix must be square. It seems fairly simple but I'm not quite sure what I'm overlooking. Any help with regards to what I may be doing wrong would be...
  27. C

    Help with Error in gravity due to uncertainty in r.

    Homework Statement Derive an algebraic expression for the error in gravity due to the uncertainty in r. Use limit error formulas and show all steps. Assume that errors in G and M are negligible. Homework Equations g=GM/r^2 The Attempt at a Solution [/B] i use the error formula but not sure...
  28. M

    Uncertainty in Average Intensity Calculation

    Homework Statement I am analysing intensities of some pictures. There are specific regions of higher intensities and so far i have managed to locate those regions automatically in Mathematica and the program returns the average intensity and standard deviation on this regions ("circles"), so I...
  29. U

    MHB OLS standard error that corrects for autocorrelation but not heteroskedasticity

    Question: By mapping the OLS regression into the GMM framework, write the formula for the standard error of the OLS regression coefficients that corrects for autocorrelation but *not* heteroskedasticity. Furthermore, show that in this case, the conventional standard errors are OK if the $x$'s...
  30. Adrian Soo

    Richardson extrapolation matlab error

    Hi everyone, I am trying to differentiate a function by means of Richardson Extrapolation in MATLAB. However, I could not run the program. Here are the outputs and its codes. Could anyone explain to me what is my mistake? The codes are based on "Numerical Methods Using MATLAB by John H. Matthews...
  31. I

    C/C++ How do I print error statements when using if and else commands in C++?

    im using the if and else commands in c++ and for the else i want the program to print an error statement. how do i do this?
  32. A

    Atwood's Machine Lab Help (proportional error)

    I have attached the lab right now I am stuck on proportional error in multiple variables I want to take the lab step by step so i can learn how to do calculate all the variables from now on. I have lab partners during the lab but I am completely clueless when I am working on it on my...
  33. T

    How can a horizontal component be of sin? Error in book or my brain?

    I've learned that the horizontal component is F cos angle not F sin angle, but I'm looking right now into the aqa physics a student book from nelson thrones, chapter 2.3 page 27, and it says that the horizontal components going to be made up of sin and the vertical out of cos... This is about...
  34. D

    Charge to Mass Lab Error Analysis

    In a lab measuring the charge to mass ratio of an electron I am having trouble with the error analysis. Specifically, this lab measured the radius of a curved path of an electron in a magnetic field (generated by Helmholtz coils with a a current 'I' running through them) with the velocity of the...
  35. J

    Finding error of secant method empirically

    Homework Statement I need to find the roots of a given equation using the secant method and matlab. I have already found all the roots, but I am also asked to find the rate of convergence for the method empirically, meaning that they want me to find the order of convergence through the set...
  36. P

    This long uncertainty viscosity problem where I need to get the error

    Any help with this basic college problem. Homework Statement The following readings were obtained in an experiment to find the coefficient of viscosity of water n by measuring the rate of flow of water through a horizontal capillary tube. Diameter of capillary tube = 1.40 mm Length of...
  37. DivergentSpectrum

    How do I accurately measure error in my n-body simulation?

    sorry for spamming the boards with all these questions lol- i promise this is my last post regarding n body problems. how do i measure error? i can't really find much on this subject. i want to use adaptive stepsize in my n body simulator I am guessing for the n-body problem i base my error on...
  38. M

    Integrating question but withe error

    Homework Statement Calculate the integral: ∫2x/(x2−11x+30) dx 2. The attempt at a solution I factored and got A/(x-6) + B/(x-5) = 2x/(x2−11x+30) Then I isolated and found A = 12 and B = -10 Then, after setting up the integral again, got 12ln(x-6) - 10ln(x-5) + C Unfortunately this is not...
  39. O

    Integral x^2*e^(-x^2) running into error function

    Homework Statement I am trying to find the expectation value of <x2> of the following function: ψ[(x,t)]=(\frac{2am}{πh})[1/4]e[-a(\frac{mx^2}{h}+it)], where h is hbar and the integral is from -∞ to ∞ Homework Equations <x2>=\intx^2|ψ[(x,t)]|2dx The Attempt at a Solution The resulting...
  40. C

    Margin of error, if all responses identical

    Hi, If I poll 10 people (with a yes/no question), and all of them respond with 'yes', should I report the rate of 'no' answers (in the greater population) is "zero plus or minus zero", or simply be confident that it is "less than one in five"? I ask because using the "margin of error" (or...
  41. S

    Fortran What could be causing the error in SAVEDATA!KEEP subroutine?

    Hi, I'm new in this space, I have a problem building a program with Fortran95 (I'm also new on this). The program it's really easy, I have to make a random generator using RANMAR subroutine here is the code: program random use aleatorio; use SAVEDATA Implicit none real, allocatable ...
  42. S

    Fortran Why Am I Getting a Fortran Memory Allocation Error?

    I am getting the following error when i try to run my program: Operating system error: Cannot allocate memory Allocation would exceed memory limit Any thoughts about that this is and maybe any suggestions about how to resolve the issue??
  43. P

    Combining three measurements of same thing to find error

    Hi All, So here is an error analysis question for you all: I am measuring the temperature of an object at three positions simultaneously. They are type K thermocouples so their individual error is 0.75% of their reading. However, I can also take long term data which shows that...
  44. S

    How did Einstein simplify the units of c?

    Hi, On p.4 of "A First Course in General Relativity", Shutz says that we redefine the units of time so that the new unit of time is the meter, where one meter is "the time it takes time to travel one meter". He then argues that: ## c =...
  45. S

    Calorimetry quantifying sources of error

    Homework Statement I am conducting an experiment to determine the specific heat of a certain metal using a typical calorimetry experiment (using a polystyrene cup). I have been asked to list sources of error and quantify them in relation to the total error in the experiment - I have thought...
  46. C

    Teaching Error in Measurement Lab

    Hello all, as a recent graduate and a new teacher, I am living in Honduras and teaching the sciences in a high school setting. I did not study to be a teaching by got my bachelors in Spanish and Physics. I am working at a bilingual school and my resources are extremely limited. My question is...
  47. Dethrone

    MHB Did I make a mistake in this integral?

    I'm really exhausted mentally, so it'll be really helpful if someone can tell me where I made a mistake. I'm rotating surfaces, and with that, I had to solve this integral: $$=\pi \int \sqrt{64-3x^2} dx$$ $$=\frac{\pi}{\sqrt{3}} \int \sqrt{\frac{64}{3}-x^2} dx$$ Let $$x = \frac{8}{\sqrt{3}}...
  48. B

    Error by Model import sab. Modeltyp in Ansoft 15.

    I try to import a sab. Modeltyp in Ansoft 15. but i receive an error that translation for the model is failed or saved file is from a later version. how can i fix the problem. Thank you .
  49. V

    Uncertainty error of resistors in parallel

    Homework Statement Find the Uncertainty of the Total Resistance of two (2) parallel-connected resistors: R1 = 2.2 kΩ ± 5\% \ ;\ R2 = 1.8 kΩ ± 20\%. Homework Equations We know that resistors in parallel are: \frac{1}{R_t}={\frac{1}{R_1±\delta_{R_1}}+\frac{1}{R_2±\delta_{R_2}}} This...
  50. gfd43tg

    Maximum error in not-a-knot spline of bessel function

    Homework Statement If you didn't already, download splineFunctions.zipView in a new window. This contains the splineE7.p and splinevalueE7.p function files. The syntax is as follows: If Xdata and Ydata are vectors with the same number of elements, then four various splines can be created as...
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