number was chosen as it gave a good balance between computational efficiency and accuracy. The parents' ages are given and discretised accordingly, education is given as an integer, where 13 is the highest level of education, indicating tertiary education. 

Gravidity is defined as the number of times that a woman has been pregnant, whereas parity is defined as the number of times that she has given birth. It must be noted that multiple births during a pregnancy are indicated with a parity of one. Gravidity and parity also provide a good indication of the reproductive health of pregnant women in South Africa. The rough set models were trained by sampling in the input space and accepting or rejecting using Metropolis et. al. algorithm (1953). The sample input space and the 

| Number   |       |      |       |      |    |       |       |       |          |        |
|----------|-------|------|-------|------|----|-------|-------|-------|----------|--------|
| LowA     | MedA  | MedB | HighB | MedC | …  | HighD | LowE  | HighE | Accuracy | Rules  |
| 6.14     | 27.03 | 5.86 | 9.31  | 1.63 | …  | 2.56  | 2.38  | 10.85 | 55.50    | 191.00 |
| 11.44    | 15.77 | 9.21 | 10.19 | 2.76 | …  | 5.71  | 0.59  | 32.67 | 59.87    | 299.00 |
| 8.56     | 24.08 | 7.01 | 8.10  | 4.62 | …  | 3.65  | 7.83  | 28.55 | 56.44    | 202.00 |
| 1.78     | 3.76  | 0.00 | 1.71  | 0.27 | …  | 3.39  | 6.54  | 19.84 | 60.77    | 130.00 |
| 4.12     | 6.33  | 1.25 | 6.86  | 1.77 | …  | 4.15  | 10.37 | 28.81 | 57.52    | 226.00 |
| 7.83     | 20.49 | 1.45 | 4.99  | 1.13 | …  | 3.36  | 5.00  | 23.70 | 62.54    | 283.00 |
| 2.68     | 25.31 | 4.98 | 6.24  | 0.32 | …  | 3.72  | 0.79  | 14.97 | 56.37    | 204.00 |

from a total of 13087. The input data was therefore the demographic characteristics explained earlier and the output were the plausibility of HIV with 1 representing 100% 