Types of statistical tests
Background
- There are many statistical tests used for biomedical research. The type of test to be used depends on the type of data, population type, distribution, and number of groups.
- This article lists statistical tests by data type and sample requirements.
Descriptive Statistics
Descriptive Statistics with one variable/outcome | ||
---|---|---|
Scale/Type of Measurement | Measure | Statistic |
Ratio or Interval / (continuous/numerical) Normally Distributed |
Proportion of normal distribution below Z score | Z |
Ratio or Interval / (continuous/numerical) Normally Distributed |
Z score at upper end of proportion of standard normal curve | Z |
Ratio or Interval (continuous/numerical) Normally Distributed |
Central Tendency | Mean |
Dispersion | SD | |
Ratio or Interval/(continuous/numerical) Not Normally Distributed |
Central Tendency | Median, mode |
Dispersion | Range, Interquartile Range (IQR) | |
Ordinal (ranks) | Central Tendency | Median, mode |
Dispersion | Range, IQR | |
Nominal (categories) | Central Tendency | Mode |
Dispersion | #of categories |
One Sample
Comparison of One Sample to a Population | ||
---|---|---|
Scale/Type of Measurement | Requirement | Test |
Ratio or Interval (continuous/numerical) |
Normal distribution or n>30 | One sample t |
Nominal (categories) | One sample binomial | |
Confidence interval for proportion | ||
np and n(1-p) >5 | Z approximation |
Two or more Groups
Comparison of Two or More Independent Samples (Groups) (one independent/predictor variable) | ||||
---|---|---|---|---|
Scale/Type of | #of Samples (Groups) | Requirement | Test | |
Ratio or Interval(continuous/numerical) | 2 | Normal distribution or n>30 and Equal variances |
T test | |
normal distribution or n>30 |
Welch's T test | |||
Rank Sum Test | ||||
>2 | Normal distribution or n>30 Homogeneous variance |
Analysis of Variance (ANOVA) | ||
Kruskal-Wallis Test^{[1]} | ||||
Ordinal (ranks) or Discrete Numerical | 2 | Rank Sum Test | ||
>2 | Kruskal-Wallis Test | |||
Nominal (categories) | 2 | Fisher's Exact test Chi Squared | ||
2 | Expected values >5 | Chi Squared | ||
Relative Risk (Rate Ratio) | ||||
Odds Ratio | ||||
≥2 | Expected values >5 | Chi Squared |
Comparison of Two or More Independent Samples (Groups) (one independent/predictor variable) | ||||
---|---|---|---|---|
Scale/Type of | #of Samples (Groups) | Requirement | Test | |
Ratio or Interval(continuous/numerical) | 2 | Normal distribution or n>30 and Equal variances |
Paired T test | |
Wilcoxon Signed Rank test | ||||
2 | Normal distribution or n>30 and Equal variances |
Repeated Measures ANOVA | ||
Friedman 2-Way ANOVA | ||||
Nominal (categories) | 2 | >20 discordant pairs | McNemar's Chi Squared | |
McNemar's Chi Squared (Exact Method) |
See Also
External Links
References
- ↑ Kruskal-Wallis Test. Statisticslecturescom. 2017. Available at: http://www.statisticslectures.com/topics/kruskalwallis/. Accessed May 22, 2017.