# regression analysis

1. ### Automating VIF calculation on mutliple linear models

I came up with this code to calculate VIF for variables for each model I am evaluating displayvif<-function(x){ for (i in 1:length(x)) vif(x[[i]]) } where x is models<-lapply(d1,function(data){lm(reformulate(termlabels=".",response=names(data)[1]),data)}) and where d1...
2. ### Interpretation of linear-log regression model (Neep Help)

Dear All, I had a problem with my data of growth in percentage regarding negative and positive values due to which I could not transform it into log and get rid of heteroskedasticity issue. However, I found out another way to get rid of negative values i.e. adding a constant with each...
3. ### Validity of the regression equation.

Along with this post, I have attached a screenshot of my assignment and I am confused about the validity of regressions equations. I plotted linear and exponential trend lines and got the regression equations. When I tried to verify the equations by substituting x-values in those equations, I...
4. ### Use of scale () function and conflicting standardized values for fixed effects

Hi, I'm currently using the scale() function in a glmer model (see below) and I'm having some inconsistencies between my standardized coefficient estimates from SAS and those in R. In SAS, the STDCOEF option in a generalized linear mixed model reports solutions for fixed effects in terms of the...
5. ### Interpreting the coefficients of my regression model

Hi all, I am a student at Bournemouth University currently undertaking a research project into the pay-performance sensitivity in AIM companies. I want to investigate the impact of firm performance on total pay. My dependent variable is total pay (inc cash + equity pay) and my independent...
6. ### How to find: Best fit regression Model

Thank you so much in advance!
7. ### Regression Using Likert Scales (Total Scores)

I conducted a survey that consisted of 5 different likert scales. I totaled the scores for each scale. I would like to know if the total scores of 4 of the scales serve as predictors of the scores on the 5th scale. I am struggling to determine which regression method, if any, is most...
8. ### Multilevel Analysis with Intercations

Hello I'd like to do a regression analysis with interactions, my data has two levels (school classes ans pupils). My variables are: Predictor = dummy variable on Level 1, dependent Variable = metric on level 1, moderator variable = metric, Level 2 I used the following command, but I am not...
9. ### Multiple imputation on categorical (dummy coded) data

Hello, I have a question regarding multiple imputation for categorical variables, and hope very much that someone can answer me. I am using SPSS 20.0. So, I have a few categorical variables with several levels (for example, color, with blue, red, green, and yellow as levels) and have...
10. ### Stepwise regression model with dependent variable categorical (help)

Hello , Can I use the step wise regression model with a categorical dependent variable? Is coding the dependent variable as 0 or 1 is enough to import it to the model
11. ### Regression analysis with independant variable (error) and multiple dependant variable

So I took a lot of data (~10000) on a machine (3D printer). For each reading, I got the error and a lot of different parameter (speed, voltage, angle, temperature etc.). My first analysis showed me that none of the parameter clearly explain my error, but a correlation is clearly visible...
12. ### How to determine number of data points and period of data to determine confidence?

Dear Statisticians I have done some experiments, with continuously data acquisition, on shrinkage measurements over time. My data shows exponential regression curves. Based on the data I want to estimate how many data points and at what time the data should be gathered, to obtain a certainty...
13. ### Analysis of a longitudinal study where interventions are received at different times

I have a data set of university students. The university has 8 different assisting programs, mostly like scholarships, for needy students to help them concentrate on their studies. Since it costs a lot of money for the university to run these programs, it opts to evaluate how effective each of...
14. ### Understanding ordinal regression

Hi! This is a really simple question, but one for which the answer continues to elude me! I understand that in a binary logit regression the resulting logit is the probability of an event occurring, defined as Ln(P/1-P) However, in an ordinal logit, in which there are multiple...
15. ### Scaling variables in regression

If you need to scale variables in order to get the correct effect size and beta weight for each variable, does this mean you also scale for both categorical and continuous variables? For example: Model1=lm(DV ~ X + Y + Z) In the above equation, is it correct to scale for x/y/z or would...
16. ### Question about splitting data

I am wondering what the most common way to handle data is wherein a participant belongs to multiple groups. For example, if you're wanting to run linear regression and look at how specific diet-type (IV) effects a specific health outcome (DV/response variable) and you have participants that are...
17. ### Moderator regression: plotting graphs from multiple product terms

This is my first time posting, so apologies if I don't make sense. I've conducted a hierarchical regression analysis. I have multiple IVs whereby there is controllability of weight (IV1) and two representing 'values for thinness' (IV2 and IV3 respectively) predicting levels of prejudice (DV)...
18. ### Logistic regression, but no negative responses?

So I am trying to model who is likely, from a list of addresses, to go to a store. I have lots of criteria about the people who have visited my store, but no data about who DIDN'T visit my store. I know if I had a 1,0 variable (visited store or not) that I could do logistic regression, but I...
19. ### 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...
20. ### Appropriate model for (repeated) data

I have some cross-sectional data, where I'm interested in estimating a relationship between the "number of items in use" in sector i of country j and the size of that sector (represented by spending power). There are other control variable. However, I have six (6) sectors and 52 countries. This...