Everything I have read has indicated that when performing ANOVA, the null and alternative hypothesis are always the following:
- $H_0$: There is no difference in the means,
- $H_a$: There is a difference in the means.
But if I have a treatment and I expect, based on past experience or literature, that this treatment would perform better than the other, can the hypothesis with ANOVA ever be:
- $H_0$: A would equal or worse than B,
- $H_a$: A would be better than B?
I realize the above can be tested with a one-tailed $t$-test, but is the same hypothesis correct/possible for ANOVA, or is it a statistical no no?