For the data in Table 1 calculate: a) The differences for the scores XD b) The mean difference MD c) Calculate the standard deviation of the difference with an SS= 693.75 Table 1 Time 1 Time 2 61 83 75 89 91 98 83 92 74 80 82 88 98 98 82 77 69 88 76 78 91 70 91 80