After analyzing the relationship between the feature RIDAGEYR and the task of predicting the person's age group, I can provide the following analysis and dictionary:

Analysis:
Based on prior knowledge, the appropriate ranges of values for the age groups can be determined as follows:
- Adult: 18 years old and above
- Senior: 65 years old and above

Dictionary:

```json
{
	"Adult": [18.0, 25.0, 35.0, 40.0, 50.0],
	"Senior": [65.0, 70.0, 75.0, 80.0, 85.0]
}
```

Please note that the given values are just examples of possible RIDAGEYR values for each target class. The actual values may vary depending on the dataset and the distribution of the target variable.