Tool

Which test? The test chooser

The decision tree: every question, every answer, every test
The decision tree: every question, every answer, every test The tree starts from one question, what kind of outcome was measured, and branches through the number of groups, independent or paired, and whether σ is known, to 17 tests. Yes No One group A difference Equivalent Independent Paired Two Three or more A number One group Two independent Same cases twice Three or more Yes / no A planned mix Another category A category Events per exposure Yes No Two numbers One group Two or more A spread z test one-sample t σ known? Welch t TOST Show what? paired t Paired? ANOVA + Tukey Groups? one proportion two proportions McNemar χ² (groups) Groups? χ² goodness of fit χ² independence Against? rate ratio Pearson r Spearman ρ Straight line? χ² variance Levene Groups? Outcome?

Questions run from left to right; the path lights up as you answer, and each leaf on the right is a test. On a phone, the tree scrolls sideways in its box.

Scenario 1 of 13

An inspector weighs 25 bottles (x̄ = 504 ml, s = 10 ml) to check a maker's claim of 500 ml.

0 of 0 right so far

Which test fits depends on what you measured, how many groups you compare, whether the groups are independent or paired, and whether σ is known. Answer one question at a time: the path lights up in the tree, and the leaf names the test with its assumptions, what to do if they fail, and the code. Or switch to the drill and name the test for a scenario yourself.

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