Based on prior knowledge, we can assume that 'Senior' age group typically refers to individuals who are aged 65 and above, while the 'Adult' age group refers to individuals below the age of 65.

Here is the analysis of the relationship between the feature RIDAGEYR and the task:

- RIDAGEYR values likely to belong to the 'Adult' age group: 20, 30, 40, 50, 60
- RIDAGEYR values likely to belong to the 'Senior' age group: 70, 80, 90, 100, 110

Based on this analysis, I have created the following dictionary:

```json
{
	"Adult": [20.0, 30.0, 40.0, 50.0, 60.0],
	"Senior": [70.0, 80.0, 90.0, 100.0, 110.0]
}
```