You wish to test the following claim (Ha) at a significance level of a = 0.02. For the context of this problem, Ha = /2 - M1 where the first data set represents a pre-test and the second data set represents a post-test. Ho: Ha = 0 Ha: Ma # 0 You believe the population of difference scores is normally distributed, but you do not know the standard deviation. You obtain pre-test and post-test samples for n = 165 subjects. The average difference (post - pre) is d = - 8.6 with a standard deviation of the differences of Sa = 40.7. What is the test statistic for this sample? (Report answer accurate to three decimal places.) test statistic = _ What is the P-value for this test? For this calculation, use the conservative under-estimate for the degrees of freedom as mentioned in the textbook. (Report answer accurate to four decimal places.) P-value =