Error Definition and 998 Threads

I understand how to compute and propagate errors but have trouble with conceptualizing all things put together. I have performed an experiment to determine a value for some quantity. This quantity depend on two variables. The first one depend in turn on some other quantities as well but I think...

Let's say I have ##F=mg \tan \alpha## and want to calculate ##F##. I know ##m=(1.0 \pm 0.5)\,\mathrm{kg}## and ##\alpha=(20.5 \pm 0.5)° ##. How to calculate ##F=( 3.7 \pm ?)\,\mathrm N##? What is the general method of determining a measurement error in these cases?

Hello everyone, I found this problem online about probability, for me, I think that to have a 2 letter palindrome is less likely because we need to have the same letter in the 2 places which gives us 26 possibilities (aa , bb, cc ....) however for words with 3 letters we have 26 possibilities...

I was imagining trying to construct a rectangle of area ##A = xy## If we give a symmetric error to each dimension ##\epsilon_x, \epsilon_y## $$ A + \Delta A = ( x \pm \epsilon_x )( y \pm \epsilon_y )$$ Expanding the RHS and dividing through by ##A## $$ \frac{\Delta A}{ A} = \pm...

When I run the application, I get an error message. This message: Fatal error too many numbers first entry. What could be the reason?

The system at my college died and I did a fresh install of ubuntu and tried to install quantum espresso after installing the required dependancies according to the instructions in the link "https://osuginoissp.wixsite.com/mysite/a-install-quantum-espresso" . But the make all command keeps...

Please check the question below as given originally. Answer given is 25%. I am unable to proceed. It is given that the half-life is underestimated by 10% therefore it must be larger than originally estimated. What I can find using the percentage error formula is ##\left(...

I have seen this formula $$\sigma=\sqrt{\frac {\sum_{i=1}^{N}{(X_i- \bar{X})^2}}{N(N-1)}}$$ but also this formula $$\sigma =\frac{\sum_{i=1}^{N}{|X_i- \bar {X}|}}{N}.$$ Which of them is correct?

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...

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...

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...

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...

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>; 🤔

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...

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...

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...

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...

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 +=...

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...

What I've done so far is find the spring force through ##F_s = -kx## ##F_s = -111*16.7## ## = -1853.7N## My conclusion was that since this is the spring force, the tension force must be just the negative of that so ##1853.7N## because the net force has to balance out, but I am horribly...

Hi everyone The following problem looks like it needs to be solved by trial and error. Is there a quicker way to do it? I had the answers (but not solutions), so I simply worked backwards to get 11^2-8^2=57. If I had to solve it, I would have made a list of the final digits you'd get if you...

Hi! so its me again. After previous problem already solved now i ran into another problem. now about BURN card. its said need model? what kind of model? I tried using .84c for all my material but doesn't seems to work! heres my code if anyone wants to try :-( c TWR-P...

If a Hookean spring-mass system is made from one mass and a spring, to produce a system with a particular oscillation frequency, it's not a problem to use the propagation of errors concept to find how this frequency responds to small errors in the mass and spring constant. If a chain of...

NOTE: I am attempting to convey the equations in this post into LaTerX format in Post #19. My result is way off. It is about 7.44 x 10^9 years. The values I use are: 1/H_0 = 14.4 X 10^9 years, M = Ω_m = 0.3103, and L = Ω_Λ = 1 - Ω_m = 0.6897. The equation I start with is the following. dt =...

Hi all, I'm having a bit hard time performing error calculations on one of the lab results I got. The lab dealt with finding collection rate of a certain material onto a wire. While inside a vial, the wire was soaked in the material for a specific period of time. Then the wire was taken out of...

Hi, PF Taylor's formula provides a formula for the error in a Taylor approximation ##f(x)\approx{P_{n}(x)}## similar to that provided for linear approximation. Observe that the case ##n=0## of Taylor's formula, namely, ##f(x)=P_{0}(x)+E_{0}(x)=f(a)+\dfrac{f'(s)}{1!}(x-a)##, is just the...

Here is the error when I run python -m pytest ERROR collecting test session _______________________________________________________________________________ ..\..\..\..\anaconda3\envs\flaskblog2\lib\importlib\__init__.py:126: in import_module return _bootstrap._gcd_import(name[level:]...

Source of my knowledge-: Encoding-: Decoding-: Other references-: Question-: There is no entry for index 7 in the dictionary while decoding, how do I fix this issue?

MCNP6 gives me a "10 particles got lost" error when I try to run the attached input file modeling a 3x3 fuel lattice surrounded in coolant. As I understand it, this error is usually related to the geometry/surface definitions of each component, but I'm unsure of what the source of the error is...

1. One of the few negative effects of quitting smoking is weight gain. The data below shows the weight gain (in pounds) of 18 respondents 12 months after they quit. If the mean gain follows a normal distribution with a standard deviation of 9 pounds, estimate the mean weight gain of the 18...

Attempt at question No. 1: ΔD = ∂D/∂h * Δh + ∂D/∂v * Δv ∂D/∂h = 3Eh^2/(12(1-v^2)) ∂D/∂v = 2Eh^3/(12(1-v^2)^2) Δh = +- 0,002 Δv = 0,02 h = 0,1 v = 0,3 ΔD = 3Eh^2/(12(1-v^2)) * Δh + 2Eh^3/(12(1-v^2)^2) * Δv Because the problem asked for maximum percentage error then I decided to use the...

Hi, PF, want to know how can I go from a certain error formula for linearization I understand, to another I do not Error formula for linearization I understand: If ##f''(t)## exists for all ##t## in an interval containing ##a## and ##x##, then there exists some point ##s## between ##a## and...

Hello, I have a problem using MinGW. When I write "make" during the installation, this error appears : $make cd ./src;make make[1]: Entering directory '/home/benji/auto/07p/src' gfortran -fopenmp -O -c maps.f90 -o ../lib/maps.o maps.f90:97:41: 97 |...

Hello We have designed an optical sensor to measure glucose. But we do not have the same changes for different concentrations. What do we need to do to be able to observe different Lifetime concentrations? In our sensor test, we used phosphorescence and glucose oxidase technology. The sensor...

Hello! If I have N points (x,y) which I know they are described by a Gaussian i.e. y(x) is a Gaussian of unknown mean and standard deviation, and each y has an associated error of ##\sqrt{y}##, is there a general formula for the uncertainty on the mean of this function? Thank you!

Let's give some context. I created a Mesh via snappyHexMesh and next I am setting the boundary conditions (BCs). First I copied the patches folder "createPatchDict" to my system's folder via the command "cp $FOAM_ETC/caseDicts/mesh/manipulation/patches/createPatchDict ./system" Taking into...

Hi everyone, I have to classify a DNA sequence with a LSTM neural network but I have a problem with the inputs shame. Both the sequence and the class are encoded with One Hot Encoding and my code is this: import pandas as pd import numpy as np data = pd.read_csv('splice.data', header = None)...

Proof: Let x be the number of dollars and y be the number of cents in the check. Then we have 100y+x-68=2(100x+y). From the hint, we get the following Diophantine equation: -199x+98y=68. Applying the Euclidean Algorithm produces...

On September 8, 2019, the 200m long vehicle carrier ship Golden Ray (carrying 4067 Kia, Chevrolet, GMC, GM, Mercedes-Benz, and Ram vehicles) capsized in St. Simons Sound, Georgia, USA The accident caused the loss of a $62 million ship, $142 million in lost cargo, and $250 million in salvage...

Hi everyone, I have used MCNP6.2 for few years. This is the first time that I encountered the error such as below: bad trouble in subroutine mars_xs_init of imcn l_list too small. I tried to run an input deck and track a bunch of decay isotopes. Is anyone has similar...

Hi, PF Sometimes it is not easy to find roots of functions. Newton gave a nice clue: the Newton's Method formula: ##x_{n+1}=x_n-\dfrac{f(x_n}{f'(x_n)}##. My concern is, now that I have understood and practiced it, comprehend what I've sketched in the summary. This is all taken from "Calculus...

Could I please ask for help with the following question: The last part follows easily from the first part. Answer from back of book for first part is: 2/(3u') <= tan(Ɵ) <= 2u What I have done is the following: Here's my diagram (I have separated the components to show the internal forces...

I am looking at the webpage for the status, and it seems to me that there is a big error in the graphics: https://webb.nasa.gov/content/webbLaunch/whereIsWebb.html?units=metric It shows the Earth such that it appears that the axis of rotation is going from the bottom-right to the lop-left...

in .y code: %union{ int ival; int *ivals; char id[20]; char *str; bool *b; } %start START %token COMMENT OP_PLUS OP_MINUS OP_DIV OP_MULT OP_OP OP_CP OP_DBLMULT OP_OC OP_CC OP_COMMA KW_AND KW_OR KW_NOT KW_EQUAL KW_LESS KW_NIL KW_LIST KW_APPEND KW_CONCAT KW_SET KW_DEFFUN...

Variance and standard deviation and other measures of error I understand. This formula doesn't behave well for data sets centered around zero and also has other problems, like scaling differently as N increases than the standard deviation or standard error. Does anyone recognize this and can...

# # A fatal error has been detected by the Java Runtime Environment: # # EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x00007ffd51d4257f, pid=9852, tid=11684 # # JRE version: OpenJDK Runtime Environment JBR-11.0.12.7-1504.40-jcef (11.0.12+7) (build 11.0.12+7-b1504.40) # Java VM: OpenJDK 64-Bit...

Hey! 😊 One box contains ten production parts, four of which have a production error. Three parts are removed from the box one after the other without putting them back. We consider the following events : A : the first production part that is removed is OK B : the second production part that...

Problem Statement: I am not quite sure how to approach this problem and would appreciate the help. I how the C/N is closely related to the SNR (Eb/N0), but the question does not give the bandwidth or data rate for me to use the formula above. From the constellation diagram, my guess is this is...

hi guys i came across this simple question about evaluating the absolute error, the solution is very simple as following : $$ m_{man} = M_{b+m}\pm\Delta\;M_{b+m}-M_{b}\pm\Delta\;M_{b} $$ so the mass of the man alone is $$ m_{man} = (M_{b+m}-M_{b})\pm(\Delta\;M_{b+m}+\Delta\;M_{b}) $$ which would...