non-linear regression

  1. L

    GAMM Question: Parameter Coefficients vs Smooth terms. When is the former sig not the latter?

    Hello, I have a couple of years experience with GAMMs and I have run several complex models that have shown some really nice time course effects - well controlled structures too. In a new study, I have what seems like a straightforward Q, but I'd like a bit of insight if possible.I'll keep the...
  2. D

    "cheating" on non-linear regression

    Hello Recently I have been struggling with multiple linear regression with gene expression analysis. With my methods I have found a few interesting transcripts that correlate with the data I'm studying. However, I know there are transcripts that may increase exponentially and those fit poorly...
  3. V

    My First Model

    Hello, I am doing a Master's and I am at the dissertation stage, and have to write and test a model empirically. However I am not sure about the functional form: Y = A(a)^Z + B(b/c)^Y + D(d)^X I want to estimate the effect of a on y. However I don't think the effect will have an elasticity...
  4. M

    Do I have a non-linear regression?

    Hello everyone, I want to start by saying that I don't have too much experience working with continuous dependent variables. I have worked more with Logistic regressions. I want to test if the numbers of Use of Force (UOF) a staff member of a mental clinic had in year 2014 predicts the...
  5. C

    Some non-linear regression equations

    Hello , I have 4 predictor variables X1,X2,X3,X4 and one response variable Y . I need some non-linear regression equations for these variables . For example one of these equations is : Y=a1.(X1^a2).(X2^a3).(X3^a4).(X4^a5) I looking for at least 5 equations except the above equation . Thanks
  6. B

    4PL Non-Linear Regression, Transforming observed y values

    Good Afternoon, I'm currently teaching my self how to fit response curves, and have run into some trouble. I currently need assistance on utilizing proper methodologies to "massage" the observed y values. Is it wise to log transform the y values, knowing that this changes the vertical...
  7. J

    Non Linear Regression Stata

    Hi everyone, Using Stata 11, I am trying to perform a nl regression that could take two writings depending on one indicator (t0 in this case) in order to estimate a, b and s: When t0=1 : nl (P= (choice^({a=0.2}-1))/(({b=0.2}^t0)*({s=0.2}^k)*(4000^({a=0.2}-1)))) When t0=0: nl (P=...
  8. C

    [Optimization – Solver] Good model fit, but wrong standard deviation coefficients

    Dear reader, I am facing an optimization problem and, at this point, I need help from someone with more knowledge than me. My goal: For a non-linear regression method, I use the solver add-in function of Microsoft Excel to obtain the equation parameters by minimizing the sum of the squares...
  9. D

    How to assess Goodness-of-fit

    I have fitted a set of data points to an exponential decay curve of the equation: y=A+Be^(-t). I wish to assess the quality of fit. Is it OK if I did a chi-squared test using X^2 = sum: (O-E)^2/E and then looked up the critical value?
  10. 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...