```json
{
	"low": [1.5, 1.7, 2.1, 2.3, 2.5],
	"high": [3.0, 3.2, 3.5, 3.8, 4.2]
}
```
Based on prior knowledge, a low grain yield for soybean cultivars is expected to have a range of around 1.5-2.5 grains per pod. On the other hand, a high grain yield for soybean cultivars is expected to have a range of around 3.0-4.2 grains per pod. These values are approximate and should be taken as general guidelines.