I am building a multivariate logistic regression model with 4 exposure variables, 3 confounders, and a binary outcome variable. (all my variables are categorical, but the exposure variables are polychotomous)
I am not a student of statistics and am doing a detailed analysis for the first time. I have done the univariate analysis already, and i read that to chose the multivariate model I need to do the likelihood ratio test. the spss output does not seem to provide the likelihood ratio values in the logistic regression output, but instead in the crosstabulations with the chi squared i was able to find it.
1. I was hoping someone could help me out with how exactly i could go about with building the model and comparing the Likelihood ratios?
2. how to produce the likelihood ratios? I have been reading theoretical math books, so i am not sure if i would have to do the comparing the ratios maually, or when they say, test the model step-wise without 1 variable at a time, does spss do that for you?