Two Types of Errors H:0=0 H:0≠0，or0>0,or0<0 Type I error:=P(Reject HoHo holds) Type II error:B=P(Accept Ho|H holds) Conventionally,there are trade-off between them, we control a for a test(significance level). and then try to minimize B. Econometrics 15-Zhuxi@SJTU 9Econometrics 15 - Zhuxi@SJTU 9 Two Types of Errors     0 1 0 0 0 1 : 0 : 0, or 0, or 0 Type I error: = P Reject H | H holds Type II error: = P Accept H | H holds Conventionally, there are trade-off between them, we control for a test(significance level) H H      b      , and then try to minimize . b