ANOVA is short for ANalysis Of VAriance. Though it seems that ANOVA is a test for variance, it is truly a test for the difference in means for more than two samples.
H0: The population means of the groups being compared are the same.
H1: At least one of the means differ from the other.
There are two important assumptions of ANOVA:
(1)Independence,Normality:Samples are randomly drawn from a normal distribution, and are independent to each other.
(2)Homogeneity of variances(方差相等):The variances for the different populations from which the samples are drawn are equal.
基于此，我们在使用ANOVA之前首先要判断方差是否相等,根据方差是否相等选择合适的ANOVA方法。（红色表示具体的检验方法，蓝色表示R中所使用的函数）
TukeyHSD
但是ANOVA的结果只能告诉我们所检测的多个样本的平均值是否存在差异，并不能告诉我们究竟是哪个样本或者是哪几个样本与其余样本不同。此时我们可以选择TukeyHSD方法进一步检测，得到更为具体的结果——任意两个样本间平均值比对的结果。
所以上述流程图可以进一步完善为：
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