# linear model

1. ### Does it change anything in a multilevel model when the predictor is a higher-level variable?

I am working on a project where I have to study the link between hospital competition and mortality (but also the duration of hospital stays). More precisely I want to determine whether the more a hospital faces competition the better it performs, and therefore the lower the mortality rate...
2. ### How to predict overall survival (Cox) based on a population?

Hi, there! First of all, I am quite excited about having found this forum, and look very much forward to learning from here. (: Say I want to devise a score index for predicting patient overall survival (OS) based on a handful of co-variates, what would be the best way to do it? Briefly, I...
3. ### Linear modelling

Hi, I need some help with a modeling query: I have fit 100,000 linear models: M ~ age + age^2, M is the frequency. I found 2,000 models were significant, but would like to narrow it down to find the most ‘extreme’ cases. Is this possible? Does anyone have any suggestions or any references...
4. ### Two effects, but not enough samples - what statistics can I do?

Dear all, I made measurements of oxygen consumption (VO2) during steady state running with 3 different shoes. The runs were performed in 5 series of 3 runs, where each of the 3 successive runs was performed with different shoes. From the results of VO2 it is seen that the place of the runs...
5. ### How to calculate residual covariance in R

I know it is may be a silly question but I am looking for an answer if I fitted a linear model c<- lm (y~ a+ b) I need to get the residual covariance matrix between traits how can I do that?? Also, if I am fiting a mixed model how do I obtain the residual covariance matrix ??
6. ### How can I model a "multiplier effect" in time series data?

I currently have data corresponding to how often a certain set of songs were downloaded. Each song has a release date, and then the number of downloads per day going forward to today. It would look like...
7. ### lm for multiple regression hangs up

I'm new to R and came over strictly to do a regression on a dataset with 28 variables and 60k entries (excel limits you to 16 variables). I watched some tutorials, read some guides, then wrote this script with the hope that I would easily get the results: mydata2 <-...
8. ### Suggestions to improve this sports model?

Based on the second table "January window spend by place..." in this article, I came up with an LM attempting to determine if, in the English soccer league, there's a relationship between the average season's end ranking in the league table (there are 20 teams, three of which change every...
9. ### Correlation?

Hello all, I have accuracy scores on 6 different tests. I have calculated the percentage of the accuracy in each test so that each of the tests has a score on the same scale (0-100%). I want to see how well do each of the 6 different tests correlate with a 7th test. I have been told I should...