# modelling

1. ### Modelling issue in regression

We have large sample, over 10,000 observations from over 2,000 companies. Collected over 5 year period. In our models, the dependent variable is audit fees paid to auditor by audit client, dollars per year (continuous variable). We use regression to analyze the data. Our issue is the measure...
2. ### Standardizing coefficients of Logistic Regression Model

While I'm trying to interpret and use coefficients of Logistic Regression Model, there are two set of problems that I'm facing Standardizing and bringing to a common scale, all the coefficients? Handling both negative and positive coefficients even after standardization? To explain with an...
3. ### Ordinal Model: Acceptability/alternatives to using mean and weighting factors

I've been asked to validate a model created by someone else and need some help on how the final score is calculated. Have put lots of detail; apologies for the post length. The output (dependent) variable is ordinal scale with 5 points (i.e. 1-5) representing an assessment of risk (not risky...
4. ### 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...
5. ### 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...
6. ### 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...
7. ### 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...
8. ### 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...
9. ### 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...
10. ### 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...
11. ### 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...
12. ### 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...
13. ### 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...