Used to compare the mean of one independent variable (with three or more groups) with one dependent variable (one outcome). Should note that the independent variable should consist of ≥ 3 categorical groups; while the dependent variable (outcome) should be a continuous variable.
There should be NO significant outliers. Outliers are data points within your data that do not follow the usual pattern.
The dependent variable should be normally distributed.
There needs to be homogeneity of variances (Levene’s test for homogeneity of variance).
For example, a researcher wants to evaluate 3 regimens of statin (high, moderate, and low-intensity statin) on the effect of LDL, and want to compare the degree of LDL reduction between the 3 regimens.
Limitation of ANOVA test, the test will tell you that at least two groups were different from each other. But it won’t tell you which groups were different. Therefore, if your test returns a significant f statistic, you may need to run a post hoc test to tell you exactly which groups had a difference in mean. On the other hand, if you do not have a statistically significant result, you would not perform any further follow-up tests (post hoc test) because there is no difference between groups.