Performing Statistical analysis is regarded as the foundations of evidence-based clinical practice, a key in the functioning of new clinical research in the evaluation and the application of research. The paper throws light on how to review and the choice of statistical procedures, analyze the associations among variables and techniques used when the clinical processes being examined are still in process. Methods for building predictive models in clinical situations, and the procedure to assess the stability of these models and other quantitative conclusions. Techniques for comparing independent events are distinguished from those used with events in a causal chain or otherwise linked. Attention then turns to study design, to the determination of the sample size needed to make a given comparison and to statistically negative studies.