8. The decision rule for testing the null hypothesis that an effect is zero against the alternative hypothesis that the effect is nonzero is reject H0 if ss/ν ssE/df = ms msE > Fν,df,α , where ss is the sum of squares calculated in rule 4, ν is the degrees of freedom in rule 2, and ms = ss/ν. Example : To test HABD 0 : {the interaction ABD is negligible} against HABD A : {the interaction ABD is not negligible}, the decision rule is reject HABD 0 if ms(ABD) msE > F(a−1)(b−1)(d−1),df,α.