Difference between revisions of "Pairwise t-test"
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| + | == Pairwise t-test == | ||
| + | * we have $n$ groups, $n > 2$ | ||
| + | * we conduct a series of [[Two-Sample t-test]]s to find out which groups are different | ||
| + | * e.g. in post-[[ANOVA]] analysis | ||
| + | |||
| + | |||
| + | === Controlling [[Family-Wise Error Rate]] === | ||
| + | It's important to modify $\alpha$ to avoid [[Type I Errors]] | ||
| + | * when we run many tests, it's inevitable that we make them just by chance | ||
| + | |||
| + | E.g. use [[Bonferroni Correction]] | ||
| + | * use modified confidence level $\alpha^* = \alpha \cdot \cfrac{1}{K}$ | ||
| + | * where for $k$ groups $K= \cfrac{k \cdot (k - 1)}{2}$ | ||
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| + | |||
| + | == Sources == | ||
| + | * [[Statistics: Making Sense of Data (coursera)]] | ||
| + | * [[OpenIntro Statistics (book)]] | ||
| + | * http://projectile.sv.cmu.edu/research/public/talks/t-test.htm | ||
| + | |||
| + | [[Category:T-Test]] | ||
| + | [[Category:Statistics]] | ||
| + | [[Category:Statistical Tests]] | ||
| + | [[Category:R]] | ||
Latest revision as of 18:58, 23 November 2015
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This is a stub. Edit it. |
Pairwise t-test
- we have $n$ groups, $n > 2$
- we conduct a series of Two-Sample t-tests to find out which groups are different
- e.g. in post-ANOVA analysis
Controlling Family-Wise Error Rate
It's important to modify $\alpha$ to avoid Type I Errors
- when we run many tests, it's inevitable that we make them just by chance
E.g. use Bonferroni Correction
- use modified confidence level $\alpha^* = \alpha \cdot \cfrac{1}{K}$
- where for $k$ groups $K= \cfrac{k \cdot (k - 1)}{2}$