Why is it people don't understand that all groups have different means given large enough N. Statistical significance has nothing to do with the magnitude of di

Why is it people don't understand that all groups have different means given large enough N. Statistical significance has nothing to do with the magnitude of difference. Effect size is what you are looking for which looks at the magnitude of the difference in means taking into account the groups variance. Also, 3 may well be statistically significant, and perhaps have a large effect size. This does not mean it is clinically significant.