For hypothesis tests that are two-tailed, the methods of Part 1 require that we need to find only the upper critical value. Let’s denote the upper critical value by FR, where the subscript indicates the critical value for the right tail. The lower critical value FL (for the left tail) can be found as follows: (1) Interchange the degrees of freedom used for finding FR, then (2) using the degrees of freedom found in Step 1, find the F value from Table A-5; (3) take the reciprocal of the F value found in Step 2, and the result is FL. Find the critical values FLand FR for Exercise 16 “Blanking Out on Tests.”

Data From Exercise 16:

Many students have had the unpleasant experience of panicking on a test because the first question was exceptionally difficult. The arrangement of test items was studied for its effect on anxiety. The following scores are measures of “debilitating test anxiety,” which most of us call panic or blanking out (based on data from “Item Arrangement, Cognitive Entry Characteristics, Sex and Test Anxiety as Predictors of Achievement in Examination Performance,” by Klimko, Journal of Experimental Education, Vol. 52, No. 4.) Using a 0.05 significance level, test the claim that the two populations of scores have different amounts of variation.