Full Model Model 2 Model 3 Model 4 Model 5 Model 6 (SE) (SE) (SE) (SE) (SE) (SE) β β β β β β N (# observations) Main exposure Covariate 1 Covariate 2 Taken out -- Covariate 3 Covariate 4 Covariate 5 Covariate 6 -- -- -- -- Interaction E x C1 Interaction E x C3 Taken out -- -- -- -- -2 log likelihood Notes: C1: 0,1,2 Removed Recoded C3: Removed outlier (Outlier is back in, Recoded C6 as C3: binary interaction E x C3 continuous for C3 (because and C3 is nominal (4 C3 is coded dichotomous categories) continuous) again.) Replaced C2 with another highly correlated variable: C6 (coded continuous). Compare to: Full model Model 2 Model 3, Model 2 Model 2 Model 5 Conclusion: Interaction C3 weaker Outlier: may have Outlier not C6 is better C6 shows predictor not threshold effect influential predictor than C2 progressive important curve; decide to leave as continuous. (Final model is therefore Model 5)
Full Model Model 2 Model 3 Model 4 Model 5 Model 6 β (SE) β (SE) β (SE) β (SE) β (SE) β (SE) N (# observations) Main exposure Covariate 1 Covariate 2 Taken out -- Covariate 3 Covariate 4 Covariate 5 Covariate 6 -- -- -- -- Interaction E x C1 Interaction E x C3 Taken out -- -- -- -- -2 log likelihood Notes: C1: 0,1,2 C3: binary Removed interaction E x C3 Recoded C3: continuous Removed outlier for C3 (because C3 is coded continuous) (Outlier is back in, and C3 is dichotomous again.) Replaced C2 with another highly correlated variable: C6 (coded continuous). Recoded C6 as nominal (4 categories) Compare to: Full model Model 2 Model 3, Model 2 Model 2 Model 5 Conclusion: Interaction C3 weaker predictor not important Outlier: may have threshold effect Outlier not influential C6 is better predictor than C2 C6 shows progressive curve; decide to leave as continuous. (Final model is therefore Model 5)
BMTRY%20747%20Project%20Part%203%20-%20spring%202015.docx