How to Choose a Statistical Test
One of the most difficult tasks in completing a statistical homework assignment is the selection of an appropriate statistic or statistical test to use.
To select the right test, ask yourself two questions: What type of data do I have? What is my objective? Then pick an appropriate statistic or test from the following table.
| Type of Data | |||
| Objective | Measurement (from normal distribution) | Rank, Score, or Measurement (from non-normal distribution) | Binomial (two possible outcomes) |
| Describe one group | Mean, St. Dev. | Median, interquartile range | Proportion |
| Compare one group to a hypothetical value | One-sample t test | Wilcoxon test | Chi-square or Binomial test |
| Compare two unpaired groups | Unpaired t test | Mann-Whitney test | Fisher's exact test (chi-square for large samples) |
| Compare two paired groups | Paired t test | Wilcoxon test | McNemar's test |
| Compare three or more unmatched groups | One-way ANOVA | Kruskal-Wallis test | Chi-square test |
| Compare three or more matched groups | Repeated-measures ANOVA | Friedman test | Cochran Q |
| Measure association between two variables | Pearson correlation | Spearman correlation | Contingency coefficients |
| Predict value from another measured variable | Simple linear regression or Nonlinear regression |
Nonparametric regression | Simple logistic regression |