modelling

  1. M

    Sum of two normal distributions

    Hello, I'm doing data analysis research and currently I'm trying to fit the simple model to a data sample. From physical speculations I know that the distribution should be a sum of two normal distributions with different parameters (mean, width, area). I fitted my data with the model and it...
  2. E

    Forecasting/Future prediction assistance

    Hi guys, I've got a bit of advertising data here and I'd like to make a model out of it which can predict future events. So I have the amount of money spent, the number of billboards we've got and how many people we think have seen the billboard. We also have the number of walk ins we...
  3. P

    GARCH modelling and forecasting

    Hi, I have a few questions regarding GARCH modelling and forecasting and it would be great if someone could help me. I am modelling oil spot prices log-return using various GARCH models: GARCH, APARCH, EGARCH... and I am trying to forecast the prices. I found using ACF and PACF plots that the...
  4. M

    Extract final values from one run of a simulation

    I ran a simulation using R and because there were a large number of permutations (>10,000) we stored the output of each permutation in a separate file. For each permutation we did 1000 runs of the simulation. The attached file contains the 1000 runs that make up one of these permutations. I...
  5. W

    Comparing self made models

    Hello! I have a quenstion about comparing models. Not models fitted by R itself, but user defined models. Ill explain through this example: Dataset: Tree Diameter Biomass Model1biomass Model2biomass 1 10 50 45 60 2 7 35 52...
  6. D

    Error in creating a raster stack - any suggestions on how to fix the problem?

    Hi I am trying to create a raster stack of several ASCII files for an environmental variable. This is what I have done so far: >files <- list.files(path=paste(system.file(package="dismo"), '/temperature', sep=''), pattern='asc', full.names=TRUE ) >files #gives me a list of the files...
  7. R

    Help with Probabilistic Modeling with many elements in simulation with unknown probs.

    I'm wanting to create a probabilistic model based on several simulations, where I have a binary outcome (go or no-go) and a variable input. The old way of formulating the proability distribution was a straight-forward, curve-fitting of the input variable versus the "go or no-go" outcomes...
  8. T

    Proc nlmixed help

    Hi, I'm using proc nlmixed to do some mixed modelling. My null model is proc nlmixed data = temp0; parms b0=-1 s2u=2; eta = b0 + u; p = exp(eta)/(1+exp(eta)); model ovpay ~ binomial(1,p); random u ~ normal(0,s2u) subject=new_laid; predict eta out=eta_0; run; And I'm...
  9. M

    Sport Statistical Modelling

    I am very interested in football and want to create a statistical model for predicting the amount of goals scored by football team by using past results (goals scored, goals conceded etc). The problem I am facing is what sort of distribution represents these football results most realistically...
  10. G

    Modelling a variable

    Hi everybody, my problem is a variable (age) that I wish to enter into linear regression - but, the variable is not linear. So, I want to model it. But, it doesn't work so far. I already tried: log10, exp, ², √, and /1. Is there anything else I could try? I already talked to a...