# What is Error: Definition and 998 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. ### B How addition of vectors works if every force is quantized

Assuming two forces applied on an object in two vector one horizontal to the object and the other vertical, By vector addition the resulting vector would be in 45 degrees. (0,1) + (1,0) = (1,1) So the object acceleration direction would be as the following graph. But if the force that...
2. ### I Uncertainties accumulate when measuring longer lengths?

Hello, It is clear that as distance being measured increases, more graduations are needed to represent a unit of measure for such distance. Each graduation in a measuring device is subject to uncertainty and error, and these errors and uncertainties accumulate with the increase in the number of...
3. ### DI controller vs no controller

If we use a DI controller the error doesnt get better.Regarding the error it is the same as we didnt have any controller at all.But does the DI controller improve the recovery time or not to not having any controller at all?
4. ### I Inductance Measurement: Error Due To Series Resistance

Hi! Please refer to the word file. I am thinking of measuring inductance of an inductor by applying a DC voltage onto it. Then, calculate L = V/(di/dt). I wonder if the series resistance (R) of the voltage source plus of the inductor under test would cause much error. So, I derive the...
5. ### I On error estimates of approximate solutions

I'm reading Ordinary Differential Equations by Andersson and Böiers. They give an estimate for how the difference between an exact and an approximate solution propagates with time. Then they give an example where they encourage the reader to check that this estimate holds. When I do that, I get...
6. ### Converting MeV/c^2 to kg

(1672 MeV/c^2) * c^2 = 1.505 * 10^20 MeV = 1.505 * 10^26 eV = 2.41 * 10^7 J Since E = mc^2, m = E/c^2 Therefore, m = 2.41 * 10^7 / (3 * 10^8)^2 = 2.68 * 10^-10 kg But the answer is 2.97 * 10^-27 kg Help! What is wrong with my logic?
7. ### I Error on a weighing scale due to wrong size

If you have say a 15 centimetre long piece of rigid plastic and the weighing scale's tray is only 10 centimetres, what is an estimate of the error that introduces in the measurement assuming the weight is still within normal parameters for the weighing scale. I was wondering what the approximate...
8. ### Is Fedoraforum.org Experiencing a 403 Error?

For the past few days I get a 403 error when trying to access fedoraforum.org (using Firefox). Is anyone else having this problem?
9. ### MCNP Problem - Bad character in column 2

hello , I am getting an error that reads as follows: 1 PX 12.5 bad trouble in imcn in routine ckchar bad character, probably a control character, in column 2Cell cards 1 0 1 -2 -7 8 10 -9 imp: n=1 2 0 2 -3 -7 8 10 -9 imp: n=0 3 0 3 -4 -7 8 10 -9 imp: n=1 4 0 4 -5 -7 8 10 -9 imp: n=0 5 0 5 -6 -7...
10. ### Experiencing PF server time outs today?

@Greg Bernhardt I've been getting a lot of connection timed out errors. Anything special going on at PF? Still using Windows 7. This is just satarted happening today.
11. ### A Standard error of the coefficient of variation

What is the standard error of the coefficient of variation in an exponential distribution?
12. ### Does the book have an error in the addition of these two vectors?

(a) $$\vec A = -\vec M+2\vec N=26\hat a_x+10\hat a_y+4\hat a_z$$ Unit Vector Formula $$\hat a_A=\frac{26\hat a_x+10\hat a_y+4\hat a_z}{\sqrt {26^2+10^2+4^2}}$$ $$0.923\hat a_x+0.355\hat a_y+0.142\hat a_z$$ The book gives ##0.92\hat a_x+0.36\hat a_y+0.4\hat a_z## Not sure how the book get 0.4 for...
13. ### I Confused about using Monte Carlo for error estimation

Hello! I have 2 probabilities ##p_1## and ##p_2## which governs the probability of measuring some events. I measure event 1 N times and get ##N_1## counts and event 2 N times and get ##N_2## counts. Then I need to build the function ##A = \frac{N_1-N_2}{N_1+N_2}##. I am trying to estimate the...
14. ### A Confused about magnitude of error

Hello! I am trying to simulate the following experiment. It is a counting experiment where the probability of getting an event after a given trial is given by: $$P = 2\left(\frac{a}{x}+\frac{b}{c}\right)^2\left(1-\cos\left(\frac{\pi x}{x_0}\right)\right)$$ where, ##a = 4\pi##, ##b = 2000\pi##...
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### C/C++ Variable defined in scope gives error depending on scope

Hi PF! The following runs if lines 5 and 11 are commented, but fails otherwise. Can someone explain what's happening here? Something with scope but I'm very lost. Thanks in advance! #include <iostream> int main() { { int* i = new int; { int b = 5; i...
16. ### Basic FMESH question: "Jmesh keyword missing error"

Can someone give me a brief explanation what are imesh jmesh kmesh values are? edit: MCNP manual says IMESH is "Locations of the coarse mesh points in the y direction for rectangular geometry or in the x direction for cylindrical geometry" Which doesnt make any sense to me... what even is...
17. ### Cosine Error: 5mm Ball Tip Stylus at 7.5° Angle

Cosine error of a measured point on the surface is not a simple value, but a vector. If the ball contacts the part surface at a point located a distance from the theoretical or nominal point then the angle between the probe and the normal vector gets larger, P1 P2 will increase. We have cosine...
18. ### Python UnimplementedError: Cast string to float is not supported

Hello everyone, I have this problem that I can't solve: I have two types of images contained in two different folders. I have to create a dataset with these images and train a cycleGAN model, but for simplicity we assume that I want to print them on monitor and forget the cycleGAN. My code is...
19. ### Why does a division by zero produce an error or undefined message?

A division by zero is a mathematical oddity, , if a computer or calculator etc performs a 1\0 they would crash, the OS prevents the execution, and displays ERROR or UNDEFINED, , , some versions of windows calculator display positive or negative infinity, , try it Any ideas on this ?
20. ### I get this error when I try to run the code MCNPX

I get this error"bad trouble in imcn in routine pass1 unexpected eof in file depletion.inp" when I try to run the code MCNPX my input file c Depletion pincell input file for MCNPX c Define cells c Cell 1: Fuel 1 0 -1.0 -4 -5 -6 c Cell 2: Cladding 2 0 -2.0 4 -7 c Cell 3: Moderator 3 0 -3.0...

40. ### Uncertainty of the Standard Deviation

Using this error propagation formula: I expressed the standard deviation (s) and the partial derivatives of s w.r.t. each data point as: This gives me an uncertainty of: , where m is the mean. Does this seem reasonable for the uncertainty of the standard deviation? I also found the thread...
41. ### I Error of the WKB approximation

hello everyone I tell you a little about my situation. I already found the approximate wavefunctions for the schrodinger equation with the potential ##V(x) = x^2##, likewise, energy, etc. I have the approximate WKB solution and also the exact numeric solution. What I need to do is to calculate...
42. ### B Error in approximation to log(223)/log(3) .... senior moment?

This is probably a silly question, but I am really stuck. A possible senior moment, is my only excuse. Here is an approximation: ##log(223)/log(3) \approx 10818288 / 2198026 ## So we have: ##log(223)/log(3) - 10818288 / 2198026 = 0.0399292## which is OK but not great -- the error shows up...
43. ### A Error signal when locking a cavity

Hello! I am trying to lock a laser to a bow-tie cavity. I managed to align the cavity to a certain degree but when I lock it, the error signal looks as below. I do get a significant power enhancement (although about 10 times smaller than expected) and the lock is relatively stable, but the error...
44. ### React - load new image - error - part 2

It works with this code! If I want to write a text next to the image do I use <div> ? I mean : return <div><div><img src={logo} alt="Logo" width="40" /></div><div>Title</div></div>; 🤔
45. ### React - load new image - error

Hey! :smile: I need some help in react. I have a code for a web application and I want to change the logo. The logo I want to use is in the public folder, in this folder there is also a favicon with the old image. In the src folder there is a folder images with the old image. In the src folder...
46. ### Comp Sci Finding Optimal h for Truncation Error O(h2)

Part (A) I have already determined the truncation error of order O(h2). Part (B) I'm struggling with how to approach this part. I do not really understand where to begin to figure out what value of h is the approximation the smallest. Is this looking for a particular range? Or are we isolating...
47. ### I Error propagation and symmetric errors

Hello! I am a bit confused about how to interpret symmetric error when doing error propagation. For example, if I have ##E = \frac{mv^2}{2}##, and I do error propagation I get ##\frac{dE}{E} = 2\frac{dv}{v}##. Which implies that if I have v being normally distributed, and hence having a...
48. ### Least count error Vs Least count

I know that least count is the smallest measurement that is possible with a measuring device. But I fail to understand the exact meaning of least count error. According to my textbook, the following is the definition of least count error. "Least count error is the error associated with the...
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### Python Any help with this error in Scipy minimize function?

Hi PF! When I execute the code below: import numpy as np from scipy.stats import t import scipy.optimize as optimizeglobal data data = np.random.normal(loc=50, scale=1, size=(2400, 1)).flatten() def L(F): M = 250 lmda = 0.97 sig_0 = F[0] for i in range(1, 12): sig_0 +=...
50. ### I need help to fix a Quantum Espresso installation error in Linux

I'm a M.Sc physics student and I need to use quantum espresso for my research project . I tried the same procedure I used to install it on the system at home as I did for the one at the College but i keep getting the same error . I can't find why . I'm also new to linux . I'm using ubuntu and I...