Sample Size Calculator

Advanced statistical sample size calculator for clinical research studies, clinical trials, and observational research with power analysis and study design methodology.

📊 Statistical Power in Clinical Research

Sample size determination is critical for clinical research validity. Insufficient sample sizes lead to inconclusive results, while excessive samples waste resources. Our calculator uses statistical power analysis to determine optimal sample sizes.

Study Types Supported

  • Clinical Trials: Randomized controlled trials
  • Cohort Studies: Prospective observational research
  • Case-Control Studies: Retrospective analysis
  • Cross-Sectional Studies: Prevalence studies
  • Diagnostic Tests: Sensitivity/specificity studies

Statistical Parameters

  • Power (1-β): Probability of detecting true effect
  • Alpha (α): Type I error probability
  • Effect Size: Clinically meaningful difference
  • Variability: Standard deviation of measurements
  • Dropout Rate: Expected study attrition

Evidence-Based Research

Proper sample size calculation ensures research validity, ethical conduct, and meaningful contributions to medical knowledge and patient care.

🔬 Research Methodology

  • Clinical Researchers: Study design and planning
  • Students: Research methodology education
  • Biostatisticians: Power analysis calculations
  • Academics: Grant proposal development
  • Pharmaceutical: Clinical trial planning

📈 Power Analysis

Calculates sample sizes needed to achieve 80% power (conventional standard) with 95% confidence intervals for detecting clinically significant effects.

Calculate Sample Size

Calculate appropriate sample sizes for clinical trials and research studies using statistical power analysis.

Cohen's d, odds ratio, or relative risk
For finite population correction

Calculating sample size...

Sample Size Results
Source: ai
Live Output (raw)