Based on prior knowledge, we can assume that senior citizens are typically aged 65 or above. Therefore, we can define the age range of seniors as 65 and above, while non-seniors would be below 65.

Here is the analysis of the relationship between the feature RIDAGEYR and the task of predicting age group (senior or non-senior):

- For the 'Adult' class (non-senior), typical RIDAGEYR values could be:
  - 20.5
  - 28.9
  - 45.2
  - 50.7
  - 62.1

- For the 'Senior' class, typical RIDAGEYR values could be:
  - 66.3
  - 70.9
  - 75.2
  - 80.4
  - 90.1

Based on this analysis, the dictionary representation would be:

```json
{
	"Adult": [20.5, 28.9, 45.2, 50.7, 62.1],
	"Senior": [66.3, 70.9, 75.2, 80.4, 90.1]
}
```