assessing the relationship between a primary covariate (a treatment, exposure, etc) and the outcome variable. Description of a predictor Role of the predictor The predictor affects both the treatment and the outcome Effect Modifier The effect of the treatment is different at different level of the predictor Mediator The predictor is affected by the treatment, and in turn influences the outcome variable Multicollinearity The predictor is highly correlated with the treatment variable Answer: (a) - (b) - (c) - (d) - Confounder