Understanding probability distributions is essential for validation planning, reliability prediction, and statistical process control. Different distributions model different types of failure modes and biological processes.
Visualize and analyze common probability distributions
Mean
100.00
Median
100.00
Mode
100.00
Variance
225.00
Std Dev
15.00
• Performance Testing: Most physiological measurements (blood pressure, glucose levels)
• Manufacturing Tolerances: Component dimensions and assembly variations
• Sample Size Calculation: Validation studies with normally distributed outcomes
Use when:
Medical Device Examples:
Use when:
Medical Device Examples:
Use when:
Medical Device Examples:
Use when:
Medical Device Examples:
Verify data follows normal distribution:
Determine best-fit distribution:
Estimate parameter uncertainty:
Compare groups or validate specifications:
FDA Guidance - Statistical Software
FDA requires validation of statistical software used for regulatory submissions. Document assumptions about data distributions in validation protocols.
ISO 14971 - Risk Analysis
Probability estimates (occurrence ratings) should be based on statistical analysis where possible, not just engineering judgment. Distribution fitting provides objective evidence.
IEC 60601-1 - Reliability
Electrical medical device standard requires reliability analysis. Weibull analysis is commonly used to demonstrate compliance with reliability requirements.