Based on prior knowledge and analysis, the relationship between BMI and the task of determining whether a person has diabetes can be investigated. Normally, BMI is used as an indicator of body fatness.

Here is the dictionary with typical BMI values for each target class:

```json
{
	"yes": [25.0, 28.5, 30.2, 32.1, 34.8],
	"no": [22.7, 24.3, 26.9, 29.4, 31.0]
}
```

Note: These values are just hypothetical examples and not based on any specific dataset. In practice, you would need to analyze a dataset to determine the actual distribution of BMI values for each target class.