Accuracy Definition and 224 Threads

  1. S

    Accuracy and sensitivity

    Hi, What exactly is the difference between accuracy and sensitivity as regards experimental apparatus? Thanks. :smile:
  2. D

    How to test forecasting accuracy of regression model?

    Hey, I have just finished running all the regressions for my thesis and I now have a nice 8-variable regression with an r² if 0.53. Almost all my hypothezised variables are significant. I am now wodering if there is a possibility to somehow test the forecasting accuracy of this model? I am using...
  3. W

    Accuracy of SR's Time Dilation & Space Contraction

    Does anyone know what is the most accurate reading of SR's time dilation or space contraction? I.e. has anyone been able to verify the accuracy of SR to 10^-15?
  4. D H

    Attitude propagation stability and accuracy

    I am verifying and validating a rotational state propagator used in a dynamic simulation package. I have found some problems and solutions to them. This post outlines the propagation, the problems, and the solutions. Some questions before I start: - Has anyone else analyzed stability and...
  5. D

    Accuracy in Space: Can 10000kg Bolts & Nuts be Precisely Screwed?

    my question is about the availability of present technology is it possible to screw a nut & bolt very ,very pricisely in space. each of them will be of 10000kg and about 0.7km most important-they will be rotating at a speed of 0.5 RPM
  6. D

    Equipment Accuracy: Explaining Micro-Amp & CRO Results

    hi all, can someone explain to me if i were to theoretically calculate current using an ammeter in small units eg micro amp's 10^-6 and physically use an ammeter to obtain results why do they differ greatly? and also when i am using a cathode ray oscilloscope (CRO), when i am measuring...
  7. R

    Pixel Density & Component Accuracy: Does Width Matter?

    The following question appeared on one of my exam papers. A CCD of pixel density 10Mpixel (1cm^-2) is used to image a component of length 10cm. Show how this does or does not meet the required accuracies of +/- 0.025mm. A similar question was asked in a previous exam where the...
  8. Pengwuino

    Quantum Mechanics and the Kochen-Specker Theorem

    What is the accuracy of this statement? "Something strange is going on in physics, something so strange, in fact, that some people who've bothered ot think about the strangenoess now declare that physics is looking more and more like Eastern mysticism. This weirdness is taking place in the...
  9. L

    Heat and Mass Proportionality: Examining the Accuracy

    I NOTICED THAT THE TIME REQUIRED FOR A GIVEN MASS OF A LIQUID IS PROPORTIONAL DIRECTLY TO THE MASS OF THE LIQUID PROVIDED THE HEAT SUPPLY IS CONSTANT,WHICH MAKES t PROPORTIONAL TO m,the heat is constant.now heat is mctheta +ml.which makes t =m^2(l+ctheta).how true is this,is there a fault i...
  10. M

    Calculating Exact Area of Ruled Surface: Accuracy and Procedure

    I've been trying to figure out how to calculate the exact area of a ruled surface. I think I've come to a solution that works, but I'm not sure it's totally accurate. The procedure is as follows: Consider two curves. A ruled surface is constructed by connecting each point on one curve to a...
  11. H

    Accuracy of f(x) when x is Accurate to 6%”

    Suppose f(x) =x^{1/4} . If x is accurate to within 6%, within what percent is f(x) accurate ? i know that %percent error = delta F/ f(x) = f'(x)*deltaX / f(x) what i don't know is how to get delta f out this this information
  12. G

    Find the sensitivity and accuracy of electronic weighing scales?

    How would I find the sensitivity and accuracy of electronic weighing scales?
  13. E

    Defining a Step Function: Checking for Accuracy

    I just want to check if I got this right. Given this graph, I need to define a step function: | ---------| C | _________|_______________ | -C |_________ | So, my definition is: C[-u(t) + u(-t)]. Thanks for checking this.
  14. Loren Booda

    Can any outcome be predicted with 100% accuracy?

    For instance, will attempts to predict comprehensively eventually prove contradictory?
  15. W

    Easy way to demonstrate the accuracy of Euler's Method

    Hi As the title says i am trying to find a good example (easy diffrential equation) to demonstrate Euler's method to explain it easily without a lot of calculations, help is appriciated
  16. M

    How Accurate Are Mood Rings in Reflecting Emotions?

    I don't really know where this thread belongs. I trust the mentor to move it, if necessary. How do mood rings work? How accurate are they? As always, any and all relevant information is appreciated.
  17. D

    Accuracy of a gravitational force approximation

    It seems to me that I've got part (a) right, but I'm not so sure about what I have in part (b). I just need to know whether or not I am on the right direction. Any help is highly appreciated. :smile: Problem The force due to gravity on an object with mass m at a height h above the surface...
  18. C

    Measuring Accuracy of a Trebuchet Project

    For a physichs project I had to build a trebuchet. I measured how for it shot, and how long it took. After some calculations I got: Vi in the X= 6.258 VI in the y= 6.64 Accel in X= 0 Accel in Y= -9.8 Distance in the X= 4.8 Distance in the Y= 2.25 Time in the X= 1.36 Time In the Y= .68...
  19. A

    Non linear curve fit - parameter accuracy

    Hi, Suppose i fit some data with a curve, using Levenberg-Marquardt (or equivalent). How do I estimate the accuracy of the parameters (by this i mean p plus or minus something). I've read somewhere that its done using the jacobian and covariance matricies I think, but not sure. Anyone know if...
  20. Z

    Theory of Accuracy: Perfect Circles & Real Life

    If you were to create a seemingly perfect circle on your computer and then zoom in on it, wouldn't it have line segments rather than all curves? Of course, with the computer it is a matter of pixels. But what about in real life?
  21. M

    Accuracy of Pi: Arguing with Dad

    My dad and I got in an argument about accuracy of pi values. He said that the ratio 22/7 will always be more accurate than any decimal value of pi. I said that the value 3.14159265358979 is much more accurate. I'm 100% certain that I am correct, but I can't really think of how to prove this...
  22. M

    Geologic Dating: Accuracy and Methods

    No, I'm not talking about courting strategies , I'm talking about the methods by which geologists date rocks and paleontologists date fossils. First off, I'd like to know what the different methods are. But, more importantly, I'd like to know how accurate they are...what is the margin of...
  23. M

    How Accurate is Movie Science in Modern Films?

    This thread has two purposes: 1) Can anyone tell me of a site (or sites) that deal with the accuracy of the science in modern movies? 2) If anyone would like to discuss, take apart, or ask questions about the science of any movie, they may do that here. As always, any and all...
  24. U

    Accuracy of Fractions vs Decimals: Why Decimals?

    For exmaple you can represent one third more accurately with fractions (1/3) than with decimals (.33 etc etc). So why do we use the decimal system ?
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