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. P

    Use Linear Approximation to Find Margin of Error

    Homework Statement For x near 0, local linearization gives the following equation. e^x ≈ 1 + x Estimate to one decimal place the magnitude of the error for −1 ≤ x ≤ 1. Homework Equations The Attempt at a Solution I'm no exactly sure what to do here to be honest, but what I thought I'd...
  2. M

    Finding elemental error (such as Hysteresis)

    Alright so I have been given a table for a transducer as follows: Operation Input range 0–1000 cm H2O Excitation 15 V DC Output range 0–5 V Performance Linearity error 0.5% FSO Hysteresis error Less than 0.15% FSO Sensitivity error 0.25% of reading Thermal sensitivity error...
  3. V

    What contributes the most to the error in the density of a cylinder?

    Homework Statement If the three quantities; mass, diameter, and height for a cylinder are measured with the same percentage error, which would contribute the most to the error in the density?Homework Equations ρ=M/V ρ=4*M/(pi*d^2*h) The Attempt at a Solution so, I tried to answer it like...
  4. N

    Fortran FORTRAN - SUBST help and error

    Hi, I am new to FORTRAN and trying to debug/compile some code passed on to me. 2 questions: - What purpose does SUBST or DSUBST serve? - When I run my Makefile I keep getting the following error: 'PGF90-S-0026-Unmatched quote' According to the PG manual this translates to 'Integer...
  5. A

    Fortran Troubleshooting Fortran Errors: How to Fix Code Compilation Issues

    Dear all, I'm write code in Fortran language when compile my program I got error message : forrtl: severe (71): integer divide by zero Image PC Routine Line Source f0511 00000000007536A5 Unknown...
  6. T

    Trapezoidal Approximation Error

    Homework Statement The Attempt at a Solution Thus my answer is N = 20. I wasn't sure if I should use ≤ or just <. Also to get 2 decimal place accuracy would using 0.005 be correct?
  7. M

    Is There a Mistake in Goldstein's Mechanics on Cos Theta Definition?

    Hello, I have the third edition of Goldstein which I have been using to learn mechanics. I believe I have found an error in the book, however normally when I feel such things I tend to either be misreading the situation or misunderstanding the concept. I checked Professor Safko's site on...
  8. J

    Error function (defined on the whole complex plane) is entire

    Homework Statement The wiki page says that error function \mbox{erf}(z) = \int_{0}^{z} e^{-t^{2}} dt is entire. But I cannot find anywhere its proof. Could you give me some stcratch proof of this? Homework Equations The Attempt at a Solution I've tried to use Fundamental Theorem...
  9. M

    Solving MIPS Runtime Error: Address Out of Range 0x00000000

    Hi there, Not sure if this is the right place to post, but I seem to get a runtime error that says: address out of range 0x00000000. I think that it's probably in the first three lines of my code, but any idea as to what else it may be? Thanks so much! .data save: .word 1,2,4 size...
  10. N

    Finding the maximum/absolute error in calculating the density of a metal sample.

    Homework Statement "You are measuring the density of a metal sample. You have determined that the mass of the sample is 63.8 grams, and your error in this result is plus or minus 0.1 g. The volume of the sample is 8.8 +/- 0.1 cm^3. What is the maximum error (in g/cm^3) in your measurement of...
  11. S

    Relative error of radius when derived from diameter

    Hi guys Have lurked the forums for a while but this is my first contribution. I am in first year physics at uni and I was having a discussion with my tutor regarding the relative error for an experiment (circular motion / moment of inertia). (I tried searching for an answer to this with no...
  12. Z

    Error in Bel's 1958 Article: Correcting Lanczos Formula

    hey all, in this link :http://gallica.bnf.fr/ark:/12148/bpt6k7258/f122.image The equation 2b is not correct I believe. Please correct me if I'm wrong. Here we go : The equation mentioned reads : Rαβλμ Rαβλρ = 2 * 1/8 * Rαβλμ Rαβλμ gμρ Now multiply out by gμρ on both sides and elevate the μ...
  13. A

    Fortran Troubleshooting Function Call Error in Subroutine

    So I am making a module to run in the main program. The module contains a subroutine and several functions. I want to call one of the functions into the subroutine but it is not getting recognized. I am just doing Real :: fct %fct is the function name that returns a real value but when...
  14. R

    Error Bounds for derivative estimation

    So we are estimated derivatives using a three point formula in class and the giving bounds for the error. I was given a table of x1=1.1, x2=1.2, x3=1.3, x4=1.4. I have to find an error bound to estimate the error for x=1.1 and 1.3 for f(x)=ex In class we did x=1.1 as follows...
  15. Darth Frodo

    G by free fall experimental error

    This isn't so much a H/W question, but we have 2 sets of values, TMax and Tmin. Δ is the difference between them. We are told to get Δ/2 and get the %uncertainty of this. Why do we halve Δ?
  16. H

    MHB How Accurate is Lagrange Interpolation for Approximating Cos(0.75)?

    Problem: Use the Lagrange interpolating polynomial of degree three or less and four digit chopping arithmetic to approximate cos(.750) using the following values. Find an error bound for the approximation. cos(.6980) = 0.7661 cos(.7330) = 0.7432 cos(.7680) = 0.7193 cos(.8030) = 0.6946 The...
  17. Y

    Finding Active & Reactive Power: Possible Error in Lecture

    here is a screenshot from one of my lectures talking about how to find active power (P) and reactive power (Q) He calculates P using 100*10 Cos (30-(-30), which I understand, though the answer he gets is 200W, but whenever I calculate it I get 500 because cos60 = 0.5 and 0.5*1000 is 500...
  18. A

    What Is the Point of Finding the Relative Error in a Vector?

    Hi all, I have a general question about relative error. Suppose that we have a vector of measurements \hat{b}=\left(\hat{b_{1}},\hat{b_{2}},...,\hat{b_{n}}\right). Furthermore, suppose that these measurements are accurate to 10%. My natural interpretation of this statement is that there is...
  19. F

    Calculating distance (and percent error) using parallax

    Hi all, This is a homework problem, but I don't think asking for help here presents any ethical issues. I'm permitted to consult my classmates and compare solutions with them as long as I do my own work, and I plan to ask my professor for help if I still feel unsure after reading your...
  20. M

    Error Analysis and Simpson's Rule to approximate integrals

    Hey there, This isn't exactly a homework question, but my question did arise while doing homework and I wouldn't know where else to post it, so here I am. I'm a Calc 2 student and covered approximations of integrals that I normally wouldn't be able to integrate today. I was going through the...
  21. L

    Why is the factor of 2 present in the expression for loss?

    Hi Guys, I am just starting readings on machine learning and came across ways that the error can be used to learn the target function. The way I understand it, Error: e = f(\vec{x}) - y* Loss: L(\vec{x}) = \frac{( f(\vec{x}) - y* )^2}{2} Empirical Risk: R(f) = \sum_{i=o}^{m} \frac{(...
  22. S

    Illegal Instruction Error in Mac terminal

    I am running a mac os x 10.7 system I am writing a fortran code which compiles, however, whenever I run my code (./file.out) all I receive in return is the message "Illegal Instruction". I have tried messing with my code and I continue to receive this message. Any help with this would be...
  23. B

    Problems with propagation of error for multiple variables

    please help by telling me whether my approach to solve the problems are right or wrong. please refer to the ATTACHMENT for the questions and my approaches... your help is highly appreciated!
  24. B

    MHB Problems with propagation of error

    I have problem regarding the propagation of error since the equations involving mixtures of multiplication, division, addition, subtraction, and powers. Please help me to clarify whether my attempts are right or wrong.
  25. B

    Problems with propagation of error

    Homework Statement I have problem regarding the propagation of error since the equation involve mixtures of multiplication, division, addition, subtraction, and powers. Please help me to clarify whether my attempts are right or wrong. Your help is highly appreciated. Thank you. PLEASE REFER...
  26. M

    Mathematica MaxRecursion(/WorkingPrecision?) Error in Mathematica 8

    I'm getting an error message that suggests my attempts to increase the variable MaxRecursion in NIntegrate aren't working. I define f[n_,b_]:=NIntegrate[q*BesselJ[0,q*b]*(-(2/(n (2+n) q^4))+(1-q^2)^(n/2) HeavisideTheta[1-q^2] ((2+n q^2)/(n (2+n)...
  27. T

    Error incurred from approximating fermi surfaces to be a sphere

    I read somewhere that the error incurred from approximating the Fermi surface to be a sphere in k-space goes as 1/N where N is the number of electrons. So, N is generally of the order 10^23. I couldn't figure out how they came up with the value. I was trying to say that the actual shape of the...
  28. J

    Proof Error Q. Conway's Functions of One Complex Variable VI

    I ask this question only to those who read or have this book: If you have Baby Rudin, it would be even better. On the page 34 of the text Conway's Functions of One Complex Variable Vol 1, it proves the Chain Rule but it seems the proof is not valid: It uses sequences to show the limit is...
  29. G

    Acres to miles: conversion problem (book error?)

    Homework Statement Problem 2.2 An acre is defined such that 640 acres = 1 mi2. How many square meters are in 1 acre? Homework Equations Solution From Table 2.1, 1 mi = 1.609 km = 1609 m 1 acre = 1/640 mi ^2 The Attempt at a Solution My solution comes from wolfram alpha 4286 m^2 BOOK...
  30. S

    Physics help please - Sources of error in lab experiments

    Physics help please -- Sources of error in lab experiments Ok so i need some help with a few labs.. some I've tried out and a few i just can't get.. what i want to know is whether the limitations and sources of errors that i wrote down for each of these labs are correct or not and what i could...
  31. G

    Error in numerical approximation of an integration

    Homework Statement a,b\in R, a<b, n\in N\\ h=\frac{b-a}{n} , x_i = a+ih , i=0..n \\ f\in C^1[a,b] we approximate the integral of f in a,b with Q_n(f) = h\left[f(x_1) + f(x_1) + ... + f(x_n)\right] Find the error R_n(f) = \int_a^bf(x)dx - Q_n(f), as function of the first derivative of f...
  32. Z

    Calculating Standard Error of Mean for 2D Histogram Data

    Hey everyone, I'm not sure if there is an effective answer to my problem, but here goes: I am working on Ramachandran plots for short peptides (3 amino acids long). For every snapshot of the protein (this would be my data point) there are two angles being recorded, the phi and psi angles...
  33. G

    Measuring error analysis with 3 variables

    Homework Statement Consider the function F(xyz)=x^4+5y^4+2yz+3. 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 be represented by the variable dz. Find an algebraic expression for the uncertainty in...
  34. C

    Prediction error in a random sample

    I have an exercise that I do not understand how to solve (statistics and probability is really my weaker part...). The exercise goes as follow: In a certain population, the random variable Y has variance equal to 490. Two independent random samples, each of size 20, are drawn. The first...
  35. R

    Center of mass of a solid hemisphere (where's the error)?

    On finding the center of mass of a solid hemisphere i came up with some different result. Here's what i did... consider a small ring at a distance r from the center of the hemisphere and one more ring at a distance of r+dr from center of the ring. let, mass of the small element formed...
  36. S

    Can anyone confirm this possible error in 'Vector Calculus' by Matthews?

    Homework Statement Find the surface integral of u dot n over S where S is the part of the surface z = x + y2 with z<0 and x>-1, u is the vector field u = (2y+x,-1,0) and n has a negative z component. Homework Equations In the text leading up to the end-of-chapter exercises (where this...
  37. W

    Proving PMI from nothing? Help find the error

    "Proving" PMI from... nothing? Help find the error! Homework Statement Prove the Principle of Mathematical Induction from the Well-Ordering Principle. Homework Equations Principle of Mathematical Induction (PMI): If A \subset \mathbb{N} satisfies (i) 1 \in A, (ii) if k \in A, then...
  38. S

    Error in Young/Freedman 13th? (Integral)

    In chapter 5 of Young/Freedman's University Physics, 13th ed., Eq. 5.10 is given as: ##v_{y} = v_{t}(1 - e^{-\frac{k}{m}t})##, where v_{y} is the time-dependent speed in the vertical direction of a low-mass, slow-moving object falling through a fluid, and ##v_{t}##, ##k##, and ##m## are all...
  39. L

    Statistics - Standard Deviation, Standard Error and Mean

    Hello, Just had a question regarding statistical analysis. I'm trying to calculate the average of 4 numbers from a data set of 6 numbers in excel without manually choosing to average only the 4 numbers. e.g. 85 20 32 45 27 3 (total mean = 35.3 desired mean = 31) 100 30 27 40 21 1...
  40. Hepth

    Error propagation with two functions, two unknowns.

    If I have two independent variables x,y, and two measurements, m1, m2 with errors. And the dependence is thus: m_1 \pm \delta m_1 = f[x,y] m_2 \pm \delta m_2 = g[x,y] Now in my case, f and g are complicated expressions of x and y with no simple solution. (Actually I think i can...
  41. clope023

    Python Python Vector Class no attribute error

    Hello all, my issue is in calling the attributes of a 3d vector class in python, this is the class I was working with: import math class Vec3: ''' A three dimensional vector ''' def __init__(self, v_x=0, v_y=0, v_z=0): self.set( v_x, v_y, v_z ) def set(self, v_x=0...
  42. A

    Wikipedia error about the complementary error function?

    Take a trip over here and explain to me what is meant by taking the double factorial of -1. If you try to let N = 1 in the remainder formula, you wind up having to take (2(0) - 1)! = (-1)!, right? This strikes me as a typo; should it be changed? If so, to what?
  43. T

    Fortran New to FORTRAN, Error message I don't understand

    Hi! I am completely new to Fortran and I'm trying to compile a source code someone else has written. I get the following error: [Error] TESTEPH.F(187); type mismatch: intg JPLEPH assigned to char*80 NAMFIL. The code around line 187: 183 C NAMFIL IS THE EXTERNAL NAME OF THE BINARY...
  44. W

    Error in Algebraic Construction or Computational Translation?

    I have an equation that I've been trying to solve. I manipulated it until I had a=f(d) and then did by best to put it into a format the computer recognizes. However when I went back to check the results against the unsimplified version of the equation, they didn't work out as they should have...
  45. H

    Does the use of error bars pertain to this experiment?

    I'm currently performing a real bench experiment that would essentially validate the results of those generated in two different computer models. Essentially, there is one (real) test setup, one computer model, and another (but different) computer model. I have ONE result from each of the...
  46. H

    Optimizing Soft Error Pulse Width for CPU Fault Injection

    Homework Statement Hi, I am trying to inject some faults into a CPU manually. But I am not sure what should the soft error (SET) pulse width should be? I know that is different in different case. Therefore, I am going to set up a random generator to generator the SET pulse width. But what range...
  47. A

    Improving propagation of error in successive calculations

    Hi, When using data in calculations, errors can be introduced by the calculations themselves; A common example of this kind of data is the atomic mass of some element; The data might be reported by NIST as: 190.233(20), which indicates that the mean is 190.233, and the maximum likelihood...
  48. Y

    [Fortrran] Some help with a code error: Segmentation Fault

    Hi, I am having a segmentation fault error just when I ask the code to print the value ipos in the program. However, If I change the print to the module, the segmentation fault does not appear. Could anyone can help know, why I can not transfer the variable ipos from the module to the main...
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