Based on prior knowledge, it is known that Body Mass Index (BMI) is a commonly used measure to assess body fat based on height and weight. In terms of age groups, seniors generally have different BMI ranges compared to non-seniors. 

To analyze the relationship between the feature BMXBMI and the task of predicting age group, we can compare the typical BMI values for adults and seniors.

Here is a dictionary that includes typical BMXBMI values for each age group:

```json
{
	"Adult": [22.5, 24.9, 28.3, 30.2, 32.6],
	"Senior": [22.0, 25.4, 27.8, 29.9, 31.3]
}
```

Please note that these values are just general examples and not derived from a specific dataset. The actual BMI ranges for defining adults and seniors may vary depending on the context and criteria being used.