t Test:One-Sided Alternatives Besides our null,Ho,we need an alternative hypothesis,H,and a significance level H may be one-sided,or two-sided ◆Hi:B>0andH:阝<0 are one-sided ◆Hi:B≠0 is a two-sided alternative If we want to have only a 5%probability of rejecting Ho if it is really true,then we say our significance level is 5%(Type I error <5%) Econometrics 15-Zhuxi@SJTU 13Econometrics 15 - Zhuxi@SJTU 13 t Test: One-Sided Alternatives Besides our null, H0 , we need an alternative hypothesis, H1 , and a significance level H1 may be one-sided, or two-sided H1 : bj > 0 and H1 : bj < 0 are one-sided H1 : bj  0 is a two-sided alternative If we want to have only a 5% probability of rejecting H0 if it is really true, then we say our significance level is 5% (Type I error < 5%)