@GramrgednAngel analysis of variance begins by asking "are any of the groups different (in terms of mean)", that is, "are there any differences among groups", and then, if there are any differences to find, it proceeds to ask "which (pairs of) groups are there differences between".So I think my usage tracks with what you are quoting from Garner, and I can go on telling my students that this is how they can be precise with their English.
