Analyzing the relationship between the feature RIDAGEYR and the task of predicting the person's age group, we can consider the following:

- In general, for most datasets, a person is considered a senior if they are 65 years old or older.
- Therefore, we can define the target classes as 'Adult' for ages below 65 and 'Senior' for ages 65 and above.

Based on this analysis, we can create a dictionary with typical RIDAGEYR values for each target class as follows:

```json
{
	"Adult": [35.0, 42.0, 50.0, 59.0, 63.0],
	"Senior": [65.0, 70.0, 75.0, 80.0, 85.0]
}
```
Please note that these age values are just examples and may vary depending on the specific dataset.