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 = 50 subjects. The average difference (post - pre) is ¯ d = 7.3 with a standard deviation of the differences of s d = 28.7 .What is the test statistic for this sample? (Report answer accurate to three decimal places.)test statistic =______________-What is the p-value for this sample? (Report answer accurate to four decimal places.)