In this lesson, among other things, we learned:

• Differentiate between means and adjusted means.
• State how ANCOVA can reduce difficulties resulting from imbalance in prognostic factors.
• Recognize situations in which using a prognostic factor as a covariate is recommended. Recognize the difficulty presented with time-dependent covariates.
• Recognize interaction effects and differentiate between qualitative and quantitative interactions.
• Select the appropriate analysis of the data among ANCOVA, logistic regression and proportional hazards.
• Modify SAS programs to perform ANCOVA and logistic regression. Interpret the relevant portions of SAS output for these analyses.
• Identify 4 approaches to model building.
• Recognize the effects of incomplete data on model-building.
• Propose two methods of validating a model from a nonrandomized study.