Find the critical values XL2 = XL21-alpha/2 and XR2 = Xalpha/2 2 that correspond to 98% degree of confidence and the sample six n = 26. XL2= XR2 Solution The lower value chi-square .99 is 11.5240. This puts 1% in the left tail. The upper value chi-square .01 is 44.3141. This puts 1% in the right tail. Thus these two chi-square values are used for the 98% confidence interval. The degrees of freedom are (26-1) = 25..