b. A selects & salesmen at random and the sales figures for the previous month are recorded. They then undergo a training course. Their sales figure for the following month are recorded as shown in the table. Test if the training course, caused an improvement in the salesmen's ability? Choose 5% level of significance. The table value for V = 7 is 1.8975. Previous month 75 90 94 95 100 90% 70 64 Following month 77 101 93 92 105 88 76 68