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.

View More On Wikipedia.org
Recent contents Top users
  1. F

    B Simple error propagation questions

    Hi, I'm looking at an Italian high-school physics textbook. The subject is uncertainty propagation, and the target is 9th grade students. The book is allegedly by J.S. Walker, but I'm not sure how much it was "redacted" by the Italian editor. I am a little puzzled by two rules that are stated...
  2. B

    B Is this a printing error? (book example problem -- radius of a molecule)

    Question :- The critical volume of a gas is 0.072 L mol-1. What will be the radius of the molecule in cm ? Answer in the book :- ##V_c = 3b \implies b = 0.024 L mol## ##\therefore## for every molecule ##b = {24 \text{cm}^3\over 6 \times 10^{23}} = 4 \times 10^{-23}\text{cm}^3## per...
  3. F

    Double Integral: Error in Calculation?

    Homework Statement I have calculate my double integral using wolfram alpha , but i get the ans = 312.5 , but according to the book , the ans is = 0 , which part of my working is wrong Homework EquationsThe Attempt at a Solution Or is it z =0 , ? i have tried z = 0 , but still didnt get the...
  4. S

    Is there an error in this paper? (modulus of elasticity vs. movement)

    NOTE: I seem to have a dental implant in which there has been a mechanical failure of the abutment, which has piqued my interest in this. The paper is here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4668729/ About 40% down, there is: *** The most commonly used retaining screws are either...
  5. S

    How Can I Resolve a Fatal Error Description of Cell 27 in MCNP?

    I am running MCNP. It gives a error massage : fatal error description of cell 27 uses 1098 words. 1000 words max. I am not able to resolve this. If anybody can explain me about this error and how to correct it. regards
  6. F

    Error propagation (tape shorter than measured length)

    Homework Statement The problem is about calculating the error on the area of a rectangular field. What is known is that the sides of the rectangle are 120 m and 180 m, and they have been measured with a 10 m measuring tape. The tape has a sensitivity of 2 cm.Homework Equations Since the area...
  7. Ketav

    Solving a System of 2 ODES with Interval conditions

    Homework Statement I am trying to solve a system of 2 ordinary differential equations using matlab. However, I am not able to get numerical solutions from the code despite having keyed in all possible solutions. Homework Equations The equations I am given are: dx/dt=A(x/t)+By...
  8. henry wang

    What's the error in 1 repeated measurement?

    Homework Statement I have only repeated a measurement once, I cannot assume it is distributed as a Gaussian because there is so few data. How can I estimate its combined uncertainty? The Attempt at a Solution Total data: x1, x2 I calculated the individual uncertainties in x1 and x2 using error...
  9. jk22

    I Complex Isomorphism Error in Lorentz Transform

    I felt upon a mistake I made but cannot understand. I consider the following rotation transformation inspired from special relativity : $$\left(\begin{array}{c} x'\\ict'\end{array}\right)=\left (\begin {array} {cc} cos(\theta) & -sin(\theta) \\ sin(\theta) & cos(\theta) \end...
  10. E

    Error propagation - inverse of an error

    Homework Statement Let t = f(g, h, A, Δm, Γ, r). For t = 2 s, the propagated error is σ = 0.02 s. Can the error of 1/t2 be simply determined using the known error in t = (2 ± 0.02) s, or must the variance formula (with all the partial derivatives and errors of each dependent variable) be...
  11. Kaura

    Taylor Series Error Integration

    Homework Statement Using Taylor series, Find a polynomial p(x) of minimal degree that will approximate F(x) throughout the given interval with an error of magnitude less than 10-4 F(x) = ∫0x sin(t^2)dt Homework Equations Rn = f(n+1)(z)|x-a|(n+1)/(n+1)![/B] The Attempt at a Solution I am...
  12. Derik

    I How Do You Calculate Error with a Single Measurement in Physics Lab Reports?

    I'm currently in first year engineering and I seem to be struggling with Physics, which is not unlikely uncommon. A simple problem I've come across is not doing correct error analysis when writing up lab reports. In my current lab, which is justifying the relationship of angular frequency...
  13. E

    B History of Error Bars in Physics

    I was reading an 1803 paper by Thomas Young (of double slit fame), "Experiments and Calculations relative to physical Optics". In it, he lists various dimensions of fringes of light and things. All without any error bars. It got me thinking, what's the history of error bars in scientific...
  14. T

    I Linear regression on data collection error

    Hi I've collected few sets of data and obtained significant different linear regression (R^2) in 2 particular sets of data . Does that indicates the 2 sets of data is not validated which might due to data collection error? For example, 20 sets of data contain linear regression of 0.900+...
  15. C

    Ideal Op-Amp Voltage sign error

    Homework Statement Above is my attempt of the answer and the problem q. The correct answer is -2V. In the solutions given to us, it has this line: I understand that V- is 0V due to the characterisitcs of an op-amp. But I don't understand where is the - V0 coming from. Any ideas...
  16. L

    Solve Newton Interpolating Polynomial for Error

    Homework Statement y=1/(x^1/4). I'm given 5 x's and 5y's. I need to write Newton interpolating polynomial and find the error. Homework Equations Ln-1(x)=f(x1)+f(x1,x2)(x-x1)+... The Attempt at a Solution With the formula above I wrote the Newton interpolating polynomial but I can't find the...
  17. J

    Poll of Polls: Examining Margin of Error & Combining Polls

    If each individual poll has a margin of error, when you combine all the polls, why do they say poll of polls has no margin of error? Shouldn't the margin of error get multiplied when you combine many polls?
  18. R

    Can't Identify Error in Calculation

    [Mentor's note: This thread was moved to the homework section from General Physics, so it doesn't use the template.] Going over a basic kinematics problem with the prompt stating vi=0, x=1000m and Δt=5 and vf and a need to be solved using average v and a. Calculated vf=200ms and a=40m/s/s. But...
  19. lep11

    Error approximation using mean value theorem for mv-function

    Obviously ##\mathbb{R^2}## is convex, that is, any points ##a,b\in\mathbb{R^2}## can be connected with a line segment. In addition, ##f## is differentiable as a composition of two differentiable functions. Thus, the conditions of mean value theorem for vector functions are satisfied. By applying...
  20. C

    Possible Error in 1m/192cm Calculation: Is it Actually 1m/1.92m?

    Homework Statement i suspect the possible error of 100cm/192cm = 1m /192 m is wrong , IMO , it should be 1m /1.92m , right ? Homework EquationsThe Attempt at a Solution
  21. J

    Elementary questions about error estimation

    Homework Statement We measure the temperature with a thermometer and we get these results: 3.3 +- 0.1 ºC 3.5 +- 0.1 ºC 3.6 +- 0.1 ºC What is the temperature? Homework Equations Average = Sum of values/amount of measurementes The Attempt at a Solution Well, I calculate the average and I...
  22. Borg

    Need a fix for Firefox SEC_ERROR_INADEQUATE_KEY_USAGE error

    I figured that I would post this in case someone may know the answer. I have a small server at home that is using a self-signed certificate. Firefox used to give a warning about this and then let you accept the certificate. However, newer versions just block the site without being able to...
  23. D

    Problem with a buck converter: my error, or the device's

    Hello everyone, I am in the process of designing a buck converter. This is the regulator I have chosen. http://www.aosmd.com/pdfs/datasheet/AOZ1242DI.pdf The input will be 13V output will be from 12 to 6 volts (will be adjusted via a thermistor on the FB voltage divider R2) Now, the issue...
  24. G

    Significant Figures & Error Analysis

    Hi, I've just had my first lab in physics and I'm having a bit of trouble understanding how to determine the significant figures of my final answers and transforming them in scientific notation. For example: Homework Statement [/B] I had to measure three sides of a parallelepiped with a...
  25. adamaero

    Calculating Wavelength Using Diffraction Grating

    Homework Statement A common method for finding wavelength is to use diffraction grating. The relationship between wavelength λ and the angle of max intensity θ for first order interference is λ = d*sinθ where d is the spacing between lines on the grating, which is the inverse of the grating...
  26. A

    B Calculating error when constant is divided by variable

    Hello everyone, I have a very simple question but for some reason, I couldn't find the exact answer to it on the internet. Let's say we have a formula y = k/x where k is constant and x and y are variables. Assume that I am given the absolute uncertainty in x how should I calculate the...
  27. S

    I Likelihood of some points fitting a derived function....

    Hello! I have some concentrical spheres with many points inside. And I need to plot the total mass of points in each shell (so between 2 spheres) versus the radius of that shell (defined as (r1+r2)/2, where r1 and r2 are the radius of the 2 spheres forming the shell). I have 10 shells so my plot...
  28. T

    Python Error of Execution While Trying to Scrape a Website

    I am trying to scrape some website. And this the code i have import urllib2 from bs4 import BeautifulSoup from urllib import URLopener from urllib import FancyURLopener import traceback,sys headers = { 'Accept':'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8'...
  29. K

    Steady state error- Control system

    Hello, I have a question about steady state error. how can we get to the C? I think it has to be Ea(G1+D)G2=C which gives(R-NH)(G1+D)G2 / (1+(G1+D)G2H)=C
  30. Y

    I What is the error on averaging?

    Let say I have a random number generator with numbers in and include between +200 to -200. We know the average has to be zero if you sample infinite number of times. How about you are only allow to sample 30 times, what is the maximum error from ideal zero in 30 random sampling? Is there a...
  31. N

    MATLAB Why am I Getting an Error Message When Plotting Functions in MatLab?

    Hey everyone, I just started, what is supposed to be a beginners course in MatLab, but I am the only one who has never used MatLab before! I'm stuck on the very first HW assignment (although I did manage to get to problem 6 out of 7) and was hoping someone could explain why I keep getting an...
  32. W

    I Error while doing multi-linear regression with minitab.

    Hi, I am having trouble doing a multiple linear regression with Minitab . Here is a screenshot of the error message I keep getting: https://www.physicsforums.com/attachments/105043
  33. Daniel McKinley

    Error in Thomas' Calculus 13th edition?

    Homework Statement Section 11-2, Page 651, Example 3 Homework Equations y = sin^3t and dy = 3cos^2t sint dt. Shouldn't there be a Minus Sign there? The Attempt at a Solution Answer is correct. But isn't there a missing Minus Sign?
  34. Guidestone

    MATLAB Matlab deployment Error because of folder permissions

    Hey guys, so I wanted to give Matlab a shot regarding programming standalone applications but I keep getting the same error whenever I use "deploytool" in the command prompt. The error message picture is attached to this message. According to the error message I must change my MATLAB current...
  35. pangru

    Error Calculation Homework: Can I Kill 1 Bird with 2 Shots?

    Homework Statement I have to shot 100(±5) to kill 50. how many shots I need to kill 1 bird? Homework EquationsThe Attempt at a Solution 100±5/50 = 2±0.1 this solution is so simple, I think it is not right - is it? :rolleyes:
  36. V

    Significant Figures and Measurement Uncertainty in Scientific Measurements

    Homework Statement We measure the period of oscillation of a simple pendulum .In successive measurements ,the readings turn out to be 2.63 s , 2.56s , 2.42s , 2.71s and 2.80s . What is the period of oscillation taking into account appropriate significant figures ? Homework EquationsThe...
  37. G

    MATLAB Persistent plot legend error in recent install of R2015b

    Hey PFers. I recently did an install of Matlab R2015b on a x64 Windows 10 PC. It doesn't matter what I plot or how I plot it (e.g., plot(), scatter(),etc.), when I use the figure dropdown menu Insert→Legend I get the following error Error using assert Too many input arguments. Error in...
  38. O

    Finding relative error for radial acceleration

    Homework Statement I'm trying to find da/a to calculate the relative possible error in the radial acceleration. The equation I have to derive from is a = 4π²n²rt ⁻² (it cannot be a = v²/r). I'm not really sure how to find da since it has 3 variables? Homework Equations a = 4π²n²rt ⁻² da/a =...
  39. R

    I Propagating Error in both numerator and denominator of ratio

    Hello, I have a set of N samples, each of which yields the measurable variables A and B. I am interested in computing the mean and standard error of the ratio A/B within the group. The catch is that I need to do background subtraction on both A and B, and the two different background values BGA...
  40. T

    I How does one derived the error bound for approximations?

    error bounds for trapezoidal rule, midpoint rule, and Simpson's rule. can anyone please show me how to derive the formula?
  41. S

    A Chi squared test for data with error

    Hi everyone. I am totally new to statistics so my question may or may not be simple! I know that for the data fitting we can do a chi squared test like: \begin{equation} \chi^2 = \Sigma \frac{(f_{data}-f_{model})^2}{(error_{data})^2}\end{equation} So I have been doing this for a while, but now...
  42. Clever Penguin

    B Cosmological data margins of error

    I am currently creating a database of all the known cosmological objects, and need to know the percentage error in the following data: Diameter of the sun: 1.3914x108 metres Mass of sun: 1.989x1030 kilograms I have the orbital period of the sun to be: 2.75x107± 9.1% years
  43. H

    A Function which measures "error"

    I have an error, denoted e(x,y) for example. It's not a norm and it isn't symmetric, that is to say: e(x,y)\neq e(y,x). My question is simply this: With such properties, is the choice of such a function a good one?
  44. Jefffff

    Best Method of Analyzing Experimental Percent Error

    Homework Statement I have performed a chemistry experiment where I analyzed how the diluting of two reactants with the same volume and initial concentration impacts the percent yield of a precipitate product. Thus my IV was concentration and my DV was percent yield. My question is what is the...
  45. D

    Percentage error in Maxwellian distribution.

    Homework Statement In computing the average kinetic energy of a molecule obeying Maxwellian distribution one use the formula ½mc2 .Calculate the percentage error incurred in the calculation. The Attempt at a Solution Here c is the average velocity of a molecule obeying Maxwellian distribution...
  46. M

    Using a set square to reduce parallax error

    Homework Statement In one of my revision guides, there is an experiment for calculating the acceleration of free fall using the electromagnet and trap door arrangement. The biggest error is in the measurement of the height over which the ball falls. The guide says: "You could reduce the error...
  47. Euler2718

    What could be causing random errors on a Windows XP computer?

    So my dad was using his dinosaur of a computer today and this error message comes up. I tried googling the code/address given, but I can only find a match for the code not the address. Any insight to this would be nice.
  48. T

    Find TX turns ratio and 'class' questions?

    Hi, Just made a small thought experiment on the train, haven't really thought about it in depth. I was just wondering, if I created the above scenario (open circuit secondary and a voltmeter), would I get a voltage (assuming there is a difference in turns for primary and secondary)? Neglecting...
  49. T

    A Solving polynomial coefficients to minimize square error

    Hi there, I'm working on a problem right now that relates to least squares error estimate for polynomial fitting. I'm aware of techniques (iterative formulas) for finding the coefficients of a polynomial that minimizes the square error from a data set. So for example, for a data set that I...
  50. A

    I Regarding Error Bound of Taylor Series

    Hi all, I am very confused about how one can find the upper bound for a Taylor series.. I know its general expression, which always tells me to find the (n+1)th derivative of a certain function and use the equation f(n+1)(c) (x-a)n+1/(n+1)! for c belongs to [a,x] However, there are...
Back
Top