Step 2: Determine the characteristics of the comparison distribution Enter all the subject's ying hours and separately calculated them into two different groups. Below B Flying Hours m (XMIAZ B or Better Flying Hours m XM "2 16 43 4 52 4 16 41 2 4 32 -16 256 31 -8 64 44 -4 16 36 -3 9 58 10 100 39 O 0 51 3 9 37 -2 4 30 18 324 36 -3 9 44 -4 16 41 2 4 55 7 49 45 6 36 62 14 196 41 2 4 52 4 16 To_tal 390 E 150 To_tal 480 998 Mean 39 Mean 48 These sample data indicate that the average ying hours of population 1 (M1) is 39, and the average ying hours of population 2 (M2) is 48. Based on the above values, the estimated population variance can be calculated by using the same formula: 82: Z (X_M)2 df Since the two groups are independent, the estimated population variances need to be 998 101) calculated on both. For population 1: SE = ( = 110.89. For population 2: 8: =