```json
{
	"low": [2.0, 2.5, 3.0, 3.5, 4.0],
	"high": [4.5, 5.0, 5.5, 6.0, 6.5]
}
```
Based on prior knowledge, the Number of grains per pod (NS) is expected to have a positive correlation with grain yield. Therefore, higher values of NS are likely to be associated with high grain yield, while lower values of NS are associated with low grain yield. Considering this relationship, the provided dictionary suggests typical NS values for each target class, with "low" including values ranging from 2.0 to 4.0 and "high" including values from 4.5 to 6.5. These values are just examples and can vary depending on the specific context or dataset.