Given data:

Weight (kg): 44-48, 49-53, 54-58, 59-63, 64-68, 69-73
No. of students: 3, 4, 5, 7, 9, 8

To compute the mean weight of a group of BBA students of St. Xavier's college, we need to follow the steps given below:

Step 1: Convert the weight range into mid-values
- For the range 44-48, the mid-value is (44+48)/2 = 46 kg
- Similarly, mid-values for other weight ranges can be calculated.

Step 2: Calculate the weighted mean
- Weighted mean formula: (Σwx) / (Σw), where w = weight and x = number of students
- For the given data, the weighted mean can be calculated as follows:

Weight range | Mid-value | No. of students | Weight (w) | wx
-------------|-----------|----------------|------------|-----
44-48 | 46 | 3 | 3x46 | 138
49-53 | 51 | 4 | 4x51 | 204
54-58 | 56 | 5 | 5x56 | 280
59-63 | 61 | 7 | 7x61 | 427
64-68 | 66 | 9 | 9x66 | 594
69-73 | 71 | 8 | 8x71 | 568
Total | | 36 | | 2211

- Weighted mean = 2211 / 36 = 61.42 kg

Therefore, the mean weight of the group of BBA students of St. Xavier's college is 61.42 kg.

Note:
- Weighted mean is used when the data has different frequencies or weights.
- In this problem, we have used the mid-values of the weight ranges to calculate the weighted mean.