Testing H0 by Means ofa Confidence Interval• Let us see how we might have arrived at this sameconclusion by using a 100(1-)% confidence interval. The95% confidence interval for is• When testing a null hypothesis by means of a two-sidedconfidence interval, we reject H0 at the a level ofsignificance if the hypothesized parameter is not containedwithin the 100(1-)% confidence interval. If thehypothesized parameter is contained within the interval,H0 cannot be rejected at the a level of significance.