error propagation

  1. P

    Propagate error with prediction interval

    I have a linear dataset with known values of X & Y in R. I treat the dataset as a linear model. I have a data point with a known value of X and an unknown value of Y. The X value has an associated instrument error. Goal: compute the prediction interval (of Y) for the data point based on...
  2. P

    Error propagation - question

    Hello, Was wondering if one could get help on how to calculate the error propagation for the following situation: I have a variable X with an uncertainty ∆X If R=C/X (where C is a number with no uncertainty), what is the correct way of calculating the uncertainty of R? Should one use the...
  3. W

    Sample size during error propagation calculation

    Hi, I have several questions regarding the calculation of error propagation. Assuming I have a group of 'A' data with mean =0.852361, sd=0.388232 and sample size=34. And I have another group of 'B' data with mean = 0.798698, sd=0.396084 and sample size=40. Now I want to calculate the...
  4. N

    Propagation of Poisson Errors

    How do I combine the asymmetrical errors when I subtract my samples from the controls? I know my low counts follow a Poisson distribution and therefor I cannot simply add in quadrature as per Gaussian errors. Thanks in advance, N
  5. J

    error propagation involving log-transformed values

    I have a question about error propagation and log-transformed data. I have a measured value of 'A' (=5.20) and an associated standard error (=0.29). I have a measured value of 'B' (=10.07) and an associated standard error (=0.65). I need to report the difference in log-transformed...
  6. C

    Clarification on Error Propagation

    I thought I understood the basic operations for error propagation (addition, multiplication, etc), but I have a few questions: 1. Is variance the only measure you can use? I only have 95% CI available to me. 2. Does multiplying/dividing a mean +/- CI by a constant preserve the error (ie CI...
  7. C

    Error propagation when dividing by fitted model

    Hoping someone can help me / point me in the right direction with this one. Seems like it should be straight forward, but just can't quite get my head around it or find the info I need. BACKGROUND: I am looking at an astronomical radio data set. For a bunch of radio sources, I have...
  8. F

    Covariance of two functions for error propagation

    Hi all, I have two functions: X=A-B Y=A+2B I need to calculate the covariance of X and Y in terms of the (known) variances of A and B as part of a propagation of uncertainty calculation to work out the error on a derived quantity Z=X/Y. All I can find information on is how to...
  9. J

    Error propagation for non-linear regression parameters

    Hi, I've been doing non-linear regression on some datasets using R. The regression outputs parameter estimation and parameter standard error (SE) for the three parameters a, n and k. I calculate the value for a new parameter f = n/k. I want to find the SE for f using error propagation. I...
  10. L

    Should the standard error (SE) of the best-fit coefficients be propagated?

    Hi all, This is how I understand it. Please correct me if I’m wrong: When fitting models to experimental data the statistical software produces a set of best-fit coefficients and automatically calculates their respective ‘asymptotic’ standard error (SE). The SE for each coefficient describes...