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AAT Bioquest

What are the limitations of ANOVA?

Posted May 19, 2022


Answer

A one-way ANOVA is designed to tell researchers that at least 2 groups are different from each other. But it cannot tell you which group is different. If you get a substantial f-statistic after conducting your ANOVA test, you may need to run other tests such as the Least Significance Difference Test to determine exactly which groups had a difference in means. 

ANOVA is ineffective when used to test a single hypothesis. This is because it is designed to test all possible alternatives to the null hypothesis. The test may not be optimal when losses are not proportional to the square of the differences among the unknown population means. While ANOVA is reliable when used with data from a normal distribution it may not generate precise p-values when the data is sourced from distributions with tails that are heavier than normal.

Additional resources

Type I error robustness of ANOVA and ANOVA on ranks when the number of treatments is large

ANOVA Calculator