Error Definition and 998 Threads

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...

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...

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...

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...

"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...

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...

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...

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...

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...

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?

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...

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...

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...

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...

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...

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...

Cadense Orcad 16.3 "Error... D_D1 is undefined" I designed a half wave rectifier circuit using resistor, Vsin and 1N4148 diode with the aid of Cadense Orcad 16.3 version. However, after running the simulation, I got an error message saying that the part D_D1 is undefined. I looked for the...

Hi all, I did simple problem, in which assembly is subjected to single load & it is fixed at other end. I used Higher Order Tet element (& tried with Hexdominent Method also) for the casting body. The vonmises stress shows the true results but when i was looking for the Max Principal...

A text says that if you calculate the linear regression of data points and you get the equation y=mx+b with an r2 value, the error in the slope is given by: δm/m=2(1-r) No explanation was given. Could someone please explain this formula? Thanks!

Homework Statement Firstly, I'd just like to point out that this is not actually a course related question. I have been trying to teach myself mathematics, and have been grappling with this for a couple of days. The book has no answer at the back for this particular question. Variables...

the following code #include<stdio.h> #include<stdlib.h> int main (int argc, char *argv[]) { int* a; *a=1; return 0; } compiles ok, but throws "Segmentation fault (core dumped)" at runtime why is that? i'm working with gcc in ubuntu. I have been able to compile and run...

Homework Statement This should be very simple: Given the following (boundary frequency for photoelectric effect): \nu = \frac{\phi}{h} what would be the error on \nu? Homework Equations The Attempt at a Solution \varphi and h are both determined through linear regression (y = mx + c). Where...

Hello, I'm trying to run a simulation program, written in Fortran 77 for the g77 compiler ( I use gcc version 3.4.6). I get the following error message when running the program: invalid number: incomprehensible list input apparent state: unit 3 named combin.fig last format: list io...

Hi, I'm evaluating a log, and I'm wondering how many words I can use. When I'm trying different exponents to narrow in on the exponent that I'm looking for, can I use words next to each equation? For example, "this is not big enough" next to the numbers that aren't close to the number I'm...

good day all.i've just written a program in fortran77 for the model of a binary distillation column.i included a PI controller in my program.To obtain the integral term of the PI,I used the explicit euler to numerically integrate the error.i would love to compare my results using another method...

Homework Statement So this is a bit of a two-part question and I'm unsure which part I'm not doing right (or both!). i) Find the closed loop transfer function of the system shown ii) Design a proportional controller for the system to give a 10% steady state error Any help, hints, suggestions...

"The precision of the argument function" error message, graph not plotted I've got a function, integratedadvthirdaltb, that I'm trying to use in plotting some graphs: thirdaltb[KP_, Ps_, C_, M_] := NSolve[Sqrt[2*M]*b + InverseCDF[NormalDistribution[0, 1], Ps]*...

Hi, I've been trying to evaluate the following integral \int_{z}^{\infty}\exp\left(-y^{2}\right)\mathrm{erf}\left(b\left(y-c\right)\right)\,\mathrm{d}y or equivalently \int_{z}^{\infty}\exp\left(-y^{2}\right)\mathrm{erfc}\left(b\left(y-c\right)\right)\,\mathrm{d}y...

Hello all I am trying to understand the closing error of a Level Survey in civil engineering. I have carried out a survey of a highway, I started the survey on a Temporary Bench Mark (TBM), I took several readings of point of interest and several change points. I ended the survey back...

[SOLVED] A hard differential equation - where is the error in my logic? Homework Statement 2xyy' + y2, where y is a function of x The Attempt at a Solution 2xyy' + y2 = 12x2 |*(1/x) => (y2)' + y2/x =12x |*ln(x), 2yy' = (y2)' => (y2ln(x))' = 12x*ln(x) => y2ln(x) = ∫12x*ln(x) =>...

I've done a decent amount of reading on the subject, and I used this method of course when reporting errors during lab experience I got as an undergraduate, but it was never quite fully explained to me why exactly we report a value +/- the standard deviation of the mean as our result. Why not...

Homework Statement In an experiment to determine the Ar of Li, the % error due to random errors was calculated to be 12.1%. However, the literature value is 6.941 and my calculated value is 7.5 which means my % error s 7.45. Homework Equations Usually, the error due to the literature...

Hi everybody; I'm not programmer or computer expert, but during working with my thesis got serious problem with my program seemingly about big size of matrices. I'm working with meshes and using Fortran to analyze entire of my mesh including nodes and elements. The biggest size of my matrix has...

I was wondering if someone could please help me understand a simple problem of error propagation going from multiple measurements with errors to an average incorporating these errors. I have looked on several error propagation webpages (e.g. UC physics or UMaryland physics) but have yet to find...

This guy just uses simple algebra to prove 4=5 and I can't find the trickery:confused: http://www.youtube.com/watch?v=iKTCTy4UsUg&feature=related

I find it hard to believe I forgot my mechanics... I think the solution manual has a mistake Homework Statement http://img225.imageshack.us/img225/8018/mech1l.jpg Homework Equations http://img337.imageshack.us/img337/8733/mechform.jpg The Attempt at a Solution...

Homework Statement Here is the problem with the solution:http://dl.dropbox.com/u/64325990/MATH%20253/Capture.PNG I don't understand how dV is the error. Isn't the error the actual value - the estimated value? In other words, ΔV-dV?

On project Eureka the following problem was posted: You and a friend like running, but your friend is much faster than you. So you can run together, you two have arranged the following system. You both start out at the beginning of a path and run at constant speeds. Your friend runs to the...

When coming into contact with a result such as a + or - b, what should one take the quantity 'b' as? Is it always the standard deviation? Or is it an arbitrary uncertainty decided by the scientist running the experiment, based on the equipment? Please help. Thanks, Andrew

I found this in my math book. It gives this supposed proof that 0=4 and asks where the error is. Note that this isn't homework. I found it at the end of the unit among other bonus problems to supposedly test ingenuity. Here it is: sin^2 \theta + cos^2 \theta = 1 \Rightarrow cos \theta =...

Hello, I am trying to calculate what the margin of error for the standard deviation would be if each data point has a margin of error E. The standard deviation (for 3 data points) is defined as σ = \sqrt{\frac{(x_{1}-μ)^{2}+(x_{2}-μ)^{2}+(x_{3}-μ)^{2}}{3}} Where μ =...

Homework Statement a. Use the trapezoidal rule with n = 4 subintervals to estimate \int_0^2 x^2 dx. b. Use the error bound to find the bound for the error. c. Compute the integral exactly. d. Verify the error is no more than the error bound.Homework Equations Here, based on the problem, a...

I am using arduino and accelerometer MMA7341 to measure the acceleration in x direction of an oscillating metal table. But the mounting of the accelerometer is tilted by a small angle (say Q) . Is it affect the acceleration?. If it is affect the acceleration in x direction , how can correct it...

Does it matter how you define the error in a numerical solution?? If you define the error as numerical solution - exact solution would you be hugely wrong even if you understood what was happening (i know it's the negative of exact - numerical). I wrote a report at uni and realized i defined...

I'm new to programming in Fortran, but have programmed for quite a while in C, Matlab, and Python. This is my code. It's incomplete at the moment (the subroutines are unreferenced), though it should still compile, but won't. PROGRAM bunkers IMPLICIT NONE SUBROUTINE...

Homework Statement Well I have written my entire program for my assignment, but I cannot get it to compile without multiple instances of the same error: "expected primary-expression before ']' token. Can anybody see a mistake I am making? I would greatly appreciate your help, thank you...

Homework Statement Hi All, I have a problem in calculating the thickness of a coating material inside a tube. The tubes inside diameter is measured before and after coating. The coating thickness is calculated by substracting the diameters and dividing by two to get the thickness of the...

Hi I've got an ARMA model, and I am struggling to theoretically quantify the benefit of using it to generate forecasts for various lead times, compared to using the mean level of the process. I think the ratio of variance of forecast error using ARMA to variance of forecast error using the mean...