What is Error: Definition and 999 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. K

    I Extract error from simulated data

    Hello! Say I have some measurements ##y_i = f(x_i|a_1,a_2,...,a_n)## for different values of ##x_i##. Here ##a_i##'s are the parameters of the function I want to fit for. For example for a linear function I would just have ##y_i=ax_i+b=f(x_i|a,b)##. I want to see how the errors on the ##y_i##'s...
  2. F

    MATLAB Can I calculate the covariance matrix of a large set of data?

    Hello everyone. I want to calculate the covariance matrix of a stochastic process using Matlab as cov(listOfUVValues) being the dimensions of listOfUVValues 211302*50. I get the following error: Requested 211302x211302 (332.7GB) array exceeds maximum array size preference. Creation of...
  3. M

    I Error on non-linearity in a linear fit

    Hello! If I have some data points, with error bars on both x and y, and I would like to fit them with a function f(x). How can I write the chi-squared in this case? For errors only on y, I would have ##\chi^2 = \sum_i(\frac{f(x)-y}{\sigma_y})^2##, but I am not sure how to include ##\sigma_x##...
  4. I

    Standard deviation and standard error

    The mean of some data was 21.2°C, the standard deviation was 2, and the standard error was 0.8. My textbook says that using one standard deviation, we would report the temperature of the substance as 21.2 ± 2°C, while using the standard error, the temperature would be reported as 21.2 ± 0.8°C...
  5. Abhisheko07

    Mathematica Mathematica error when solving a DE -- "exceeded RecursionLimit"

    Homework Statement:: I don't know where the mistake is happening. I need to solve the give differential equation in mathematica and have to plot it but i am facing problem in doing so. Can anyone help me in this? Relevant Equations:: I have attached the picture of equation as well as my...
  6. jubayer ahmed

    Are My Nets Aligned with Pins in PSpice(9.1) Netlist Error?

  7. W

    A Error in (Multi)linear Regression

    Hi, I keep reading varying accounts on conditions needed to " justify" the use of ( multi) linear regression to model data. Specifically, I have seen several authors require errors to be normal, i.i.d , whilr others only require the errors be i.i.d with mean 0. Just where is the assumption of...
  8. G

    I Strange result from Bianchi identity, me spot the error

    I have accidentally derived a very wrong result from the contracted Bianchi identity and I can't see where the error is. I'm sure it's something obvious, but I need someone to point it out to me as I've gone blind. Thanks! Start with the contracted Bianchi identity, $$ \nabla_a \left(...
  9. Athenian

    Finding the Relative Uncertainty for the Standard Error of the Mean

    While I will not be showing the graph here, I am trying to dissect what the question even means. While I do understand that relative uncertainty can be found via the equation ##\frac{\sigma_A}{A}##, I do not understand how I can find the "relative uncertainty of SEM". Does anybody here have any...
  10. H

    Chemistry Calculation Error: 0.19 = (0.14 - 0.13) - 0.06/2*log(1/(0.1*[Pb2+]))

    My calculation: (A) 0.19 = (0.14 - 0.13) - 0.06/2*log(1/(0.1*[Pb2+]) => [Pb2+] = 4.6*10^6 I wonder where I did wrong. Thanks!
  11. T

    Is it okay to add error bars into a histogram plot?

    I made a histogram based off a dataset and I calculated the uncertainty of the measurements and I included the error bars into my histogram. Is that okay? I am asking because I never seen error bars included with a histogram. I have included an image of my histogram below:
  12. OmkarE11

    Error in ANSYS Explicit Dynamics

    I am tring to simulate impact of cricket ball on a bat. Whenever I try to simulate with custom materials it shows an error like 'Solver initialization failed. See the log file.' But when I carry out with steel as the material it works fine. Please help.
  13. Guillermo Navas

    I Thorne's error in explaining gravitational time dilation

    In Box 2.4 of the book "Black Holes & Time Warps" by Kip S. Thorne, he explains gravitational time dilation using the equivalence principle. For this he uses an experiment thought analogous to the one used by Einstein in 1911 to postulate the existence of a gravitational Doppler shift, but...
  14. fluidistic

    Puzzled about the non-teaching of Monte Carlo method(s) for error analysis

    Say you have measured several quantities and you can calculate the value of a physical quantity as a sum/product of the several measured quantities, and you are interested to calculate the uncertainty of that physical quantity. I have just learned about the Monte Carlo method applied to error...
  15. Y

    MNCP5 error: Program Exception - stack overflow

  16. H

    Finding My Calculation Error: Where Did I Go Wrong?

    My calculation is as attached. Where am I wrong?
  17. M

    Biology Types of Error when taking an EEG

    Hi, Question: I was recently working on a homework problem that asks us to list the different sources of error in an electroencephalogram reading and how we deal with these errors. I was struggling to find sources on the internet, so was hoping to ask whether there are any good sources which...
  18. Arman777

    I Question about data analysis and error

    Let us suppose we have one constant variable ##b \pm \delta b = 20 \pm 1 ## and one function that depends on ##x ##, such as, ##a(x) \pm \delta a ## The problem is I want the difference between ##a(x) ## and ##b ## to be ##0 ##. Let me denote this difference as ##c \pm \delta c ##. To...
  19. Arman777

    I Error propagation of a variable for an integral

    I have an integral that depends on two parameters ##a\pm\delta a## and ##b\pm \delta b##. I am doing this integral numerically and no python function can calculate the integral with uncertainties. So I have calculated the integral for each min, max values of a and b. As a result I have obtained...
  20. yucheng

    What's the error in my solution (Freight car and hopper)

    Textbook solution: ##v## is the instantaneous velocity, $$P(t)=(M+b t) v$$ Then $$impulse = \Delta P = (M+b t) v = \int^{t}_{0} F dt'$$ Thus $$v=\frac{F t}{(M + bt)}$$ What I did instead was: Let ##M## be the instantaneous mass, and ##M_0## be the initial mass, then $$M=M_{0} + b t$$...
  21. yucheng

    Rocket propulsion equation: what's the error here?

    Equation for rocket motion: $$\frac{d \mathbf{P}}{d t} = M\frac{d \mathbf{v}}{d t} - \mathbf{u}\frac{d M}{d t}$$ But $$\mathbf{F}=\frac{d \mathbf{P}}{d t}=M\frac{d \mathbf{v}}{d t}$$ So $$M\frac{d \mathbf{v}}{d t} = M\frac{d \mathbf{v}}{d t} - \mathbf{u}\frac{d M}{d t}$$ And $$-...
  22. Z

    Why Are There Floating Point Errors When Parsing Data in Pandas?

    I am parsing data from an excel sheet using pandas ExcelFile class and read_excel function. I noticed that when reading the file, there are floating point errors in the results. For example, a cell that contains 25.15 will be 25.149999999999977 in the pandas data frame. The value 25.15 in Excel...
  23. TiGuru22

    Maxwell3D Error -- Unable to locate COM Engine on 'Local Machine'

    I am attempting to solve a rather simple induction problem in Maxwell3D that I have solved before. But this time when I run it I am getting this error and can not seem to find a solution in ANSYS? I am running ANSYS Suite 2020 R1 Thank you in advance if anyone has a possible.
  24. L

    Thermodynamics: gas expansion formula or approximation error?

    FIRST TYPE: REVERSIBLE PROCESS At the temperature of 127 ° C, 1 L of CO2 is reversibly compressed from the pressure of 380 mmHg to that of 1 atm. Calculate the heat and labor exchanged assuming the gas is ideal. Q = L = - 34.95 J CONDUCT 380 mmHg = 0.5 atm L = P1 * V1 * ln (P1 / P2) = 0.5 * 1...
  25. Adams2020

    The sources of error in a diffraction grating experiment

    In a diffraction grating experiment, what can be the sources of error and also what effect do these sources have on the unknown quantity (wavelength) in the experiment?
  26. W

    Runner's track distance error problem

    Here is the official solution: I don't understand this solution. Firstly why can the author assume wlog that slower runner ran exactly 1 mile? Secondly, if 3.3ft is indeed the max error then worst case scenario is that first runner's track was 3.3 below actual length and 2nd was 3.3 over...
  27. person123

    I Computing the Speed of Traveling Waves in 2 Dimensions

    I have a 2-dimensionsal smooth function ##f(x,y,t)##. There may be multiple traveling waves across the domain. None of them are precisely traveling waves (the shape of the wave changes as it travels). Here is how one of these waves would look in 1-dimension: I want to find the speed of these...
  28. J

    B Implicit error margins based on significant figures

    WARNING: Topic is very pedantic. I have used a set of different physics books over the years, and they have all had a focus on the topic of significant figures, error margins and measurement. I have never quite understood these concepts fully and the relationships between them. One aspect I...
  29. docnet

    Computing the second fundamental form - can you spot the error?

    Hi all. We are computing the second fundamental form corresponding to a surface. The correct answer should give the coefficients 2, 0, and -2 for IIuu, IIuv, IIvv We have only been able to compute IIz, and not IIx, IIy where we have functions instead of 2, 0 and -2. We are 99% certain that...
  30. C

    Error in Sadri Hassani's Mathematical Physics

    I am reading his excellent book "Mathematical Physics Part 1, Second Edition", which has benefited me a lot in many ways. However, I have a doubt about the correctness of the theorem 2.3.23, which states that for any subspace U of V, the map T ' : V/U -> T(V) defined by T ' ([a]) = T|a> is...
  31. S

    How Is the Variance Used as Weight in Half-Life Error Analysis?

    What is meant by the constant background and how would one deduce the half-life IF not from the fit?
  32. M

    MHB Calculating Integral with Simpson's Rule for Error < $0.5\cdot 10^{-3}$

    Hey! 😊 Calculate using the Simpson's Rule the integral $\int_0^1\sqrt{1+x^4}\, dx$ approximately such that the error is less that $0,5\cdot 10^{-3}$. Which has to be $h$ ? So we use here the composite Simpson's rule, right? An upper bound of the error of that rule is defined as...
  33. Z

    Chg_mem error problem with MCNP

    Hi, I have a problem with MCNP. The problem is : the input file can run correctly on WindowsXP system,but when I run it on a more powerful computer with win10 system , the MCNP showed "chg_mem error". How to solve this problem? can MCNP only operate on winXP or win2000 system?
  34. I

    Comp Sci C language "too many arguments for format" error

    I have a problem there,I want to Users decide a,b,c,d,e numbers. if I write printf("enter numbers:"); scanf("%d",&a); printf("enter numbers:"); scanf("%d",&b);... if ı do like that ,it has not any problem but its not effective,Program always asking number a,b,c etc. My wish is...
  35. T

    Estimating Error w/ Trap and Simpson's Rule when Values are Equal

    I'm confident in calculating the beginning values. Only question I had was whether in this graph y2 is assumed positive or negative. Obviously f(pi)= negative value, but is y2 negative or is it = |f(pi)|. Assuming the latter, it all makes sense and when I sum the two Simpson's Rule estimates...
  36. haushofer

    I Error analysis: simple but confusing matter

    Dear all, We learn students to work with significant figures. I guess we all know those rules of thumb. Now imagine I have an expression like L = 2x, where x is a length a the 2 is an amount, i.e. the value of a discrete 'function'. If x=0,72 m (2 significant figures), then L = 1,44 --> 1,4 (2...
  37. Y

    Help with a build error in Visual Studio

    This is a very simple program about Class with Inventory.h, Inventory.cpp and source.cpp. I reduced to very simple just displaying two message and it just won't build. It gave me error message I don't follow even after reading the error code online. I follow the example and syntax from the book...
  38. Buzz Bloom

    I What is the density of hydrogen atoms in the Universe?

    UNITS m is meters kg is kiliograms K is degrees Kelvin s is seconds J is joules u is daltons = 1.66053906660(50)×10−27 kg https://en.wikipedia.org/wiki/Dalton_(unit) 1 pc = 3.085678 x 1016 m CONSTANTS MH = mass of hydrogen atom = 1.007825 u = 1.673532784796145 ×10−27 kg...
  39. K

    I Linear regression with error term

    I'm not a statistician, but this has been bothering me for a bit. Suppose we have the simple model Y= aX + b + U where Y,X and U are taken to be random variables representing the explanatory variable, the independent variable and the error term respectively. In the case of a stochastic...
  40. T

    Evaluate the Taylor series and find the error at a given point

    I have the following function $$f^{(0)}\left(x\right)=f\left(x\right)=e^{x}$$ And want to approximate it using Taylor at the point ##\frac{1}{\sqrt e} ## I also want to decide (without calculator)whether the error in the approximation is smaller than ##\frac{1}{25} ## The Taylor polynomial is...
  41. O

    I Derive local truncation error for the Improved Euler Method

    I'm trying to find the local truncation error of the autonomous ODE: fx/ft = f(x). I know that the error is |x(t1) − x1|, but I can't successfully figure out the Taylor expansion to get to the answer, which I believe is O(h^3). Any help would be greatly appreciated!
  42. Y

    Machine Learning - Empirical Error

    I understand everything in this equation except for the summation. I understand it's the average error over the sample. But why do we need the "1"? Moreover wouldn't the error be the absolute value of the hypothesized value minus the concept value? Meaning | h( x_i ) - c( x_i ) | because you...
  43. Y

    Mysterious Error: Can You See Why?

    I encountered a strange error. I have 2 EXACTLY same code in this program, I just use /* */ to disable one or the other. The bottom one works, the top one giving me error. I literally copied the content inside main() from the bottom to the top, still, the top one fails and bottom works...
  44. M

    Question Error? (epsilon-delta proof of a limit)

    I can not follow this mathematically. I am guessing one of the signs is incorrect? Can anyone verify ?
  45. Y

    C/C++ Please help on a C++ error message I don't understand (stack corruption)

    I have an error on this program I don't understand, it said stack corrupted around the 2 dimension array sales. //2D sales in divisions in quarters. #include <iostream> #include <iomanip> using namespace std; int main() { const int numDiv = 3;// 3 divisions const int numQtr = 4; // 4...
  46. nomadreid

    I Connection of zeta to primes: less Euler than error or L-functions?

    Often I read that the Riemann Hypothesis (RH) is related to prime numbers because of the equivalence on Re(s)>1 of the zeta function and Eurler's product formula , but is it more accurate that the relevance of the RH to primes (or vice-versa) is either that the RH implies formulas for the...
  47. S

    Correct statement about error and uncertainty

    I know option (a) and (c) are wrong but I don't know the difference between option (b) and (d) because I think they are the same (taking average to get more accurate reading and reduce random error). My guess is (b) because I think for (d) the fractional uncertainty maybe can stay the same...
  48. Y

    MHB Squared Error of Estimation

  49. S

    What is zero error of a measuring instrument ?

    Is this correct? "The systematic error in a measuring instrument due to non-uniform or wrongly marked graduation due to which a measurement may be less or greater than actual measurement is called zero error of the measuring instrument". Another one: The measuring instruments are combination...
  50. aspodkfpo

    An error made in a kinematics question about a spring launcher?

    Genevieve the galah wants to test out her new creation - the Nifty Numbat Launcher. It consists of a large, ideal spring with equilibrium length l1 = 1.7 m and spring constant k=41 N/m. The spring rests upon a ramp of length l1 inclined at an angle β=30∘ to the horizontal. The spring is attached...
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