Evidence-based practice (EBP) integrates the best available research evidence with clinical expertise and patient values to optimize clinical decision-making and patient outcomes. The scientific foundation of EBP rests on understanding the hierarchy of evidence and the biostatistical principles that determine the reliability of clinical findings. Systematic reviews and meta-analyses occupy the apex of the evidence hierarchy because they aggregate data from multiple randomized controlled trials (RCTs), reducing random error through increased sample size and allowing detection of effect sizes too small for individual studies to identify. RCTs are the gold standard for evaluating therapeutic interventions because randomization distributes both known and unknown confounding variables equally between groups, isolating the effect of the intervention from selection bias and confounding. The PICO framework (Population, Intervention, Comparison, Outcome) structures clinical questions to enable efficient literature searches and precise evidence retrieval. Critical appraisal of research requires understanding key biostatistical concepts: sensitivity (true positive rate — probability that a test correctly identifies disease), specificity (true negative rate — probability that a test correctly identifies absence of disease), positive predictive value (probability that a positive result...