{a} Use the results for the ANS-2P outcome reported in Table 2 of the paper to test the null hypothesis that the mean pain for lavage is no different than for placebo, versus the alternative that the mean pain for lavage is less than that for placebo at 1 year after surgery. Assume normality of the pain measures and test at signicant level 0.05. C'a'learl}.r explain your procedure and conclusion. VARIABLE BEFORE PROCEDURE AFTER PROCEDURE 2 WK 6 WK 3 MO 6 MO 1 YR Placebo group No. with data 59 59 57 56 57 54 Score 59.5+18.5 47.9+23.9 50.8+23.2 50.1+21.3 50.0+20.7 53.6+22.1 Lavage group No. with data 61 59 57 59 59 57 Score 59.3+16.7 51.9+20.3 52.4+22.1 53.7+23.1 54.8+21.6 57.8+23.5