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🌱 來自: Huppert’s Notes
Other Statistical Concepts and Formulas🚧 施工中
Other Statistical Concepts and Formulas
• Standard deviation (SD): For normal distribution, 68% of results within one SD, 95% of results within two SDs, 99% of results within three SDs
• Standard error of the sample mean (SEM): SD/√n, where n = sample size
• p-values: Probability that result achieved by chance, e.g., p = 0.01 means 1% probability that the result occurred by chance
• Confidence interval (CI): Mean +/– Z(SEM); when Z = 1.96, calculates 95% CI
- When comparing means, if the 95% CI includes 0, then there is no difference (assuming significance is a p-value <0.05)
- When comparing OR or RR, if the 95% confidence interval includes 1, then there is no difference (assuming significance is a p-value <0.05)
• Comparing means:
- T-test: Compares Two means
- ANOVA: Compares three or more means
• Comparing categorical variables:
- Chi2: Compares 2+ proportions (Categorical variables)
• Error:
- Type I error (α): Stating that there is an effect when none exists (α <0.05)
• False positive rate = FP/(FP+TN)
- Type II error (β): Stating that there is not an effect when there really is one
• False negative rate = FN/(FN+TP)
- Power (1-β): Probability of rejecting the null when it is false