Tagged Questions

1
vote
2answers
94 views

Non-normality and heterogeneity in ANCOVA

I am performing an ANCOVA. My dependent variable is the number of days a student is absent from school. As one can imagine, this variable is not normal, so I performed a log10 transformation. When I ...
0
votes
0answers
69 views

How to transform an independent variable with parabolic shaped logit plot in logistic regression?

I am building a logistic regression model. I have created some ratio variables. When I look at the logit plot (log odds) of these ratio variables, some of them follow parabolic shape. I am wondering ...
1
vote
1answer
42 views

Preprocessing of non-linear and censored variables

I now ran into two variables that give me problems. I know that I want to try to include them in the final model, but I'm unsure how the values should be treated in order to reflect the true nature of ...
1
vote
0answers
52 views

What are some common tools, initial approaches to data in a prediction problem when facing too many predictors?

If one is given several hundred features (of both categorical and continuous type) what are some approaches to determining which features to keep or even drop? Data as such is difficult to visualize ...
6
votes
1answer
289 views

Is it necessary to perform a transformation on proportion data if it's reasonably well behaved?

If you're modelling a proportion response against numerous predictors that are also proportions, is it necessary to transform the response if the standard OLS model is seemingly well behaved? By well ...