To analyze the relationship between the feature BMXBMI and the target task of predicting age group (senior or non-senior), we can use prior knowledge to determine the appropriate ranges of values for each age group.

Based on general guidelines for BMI categories, we can define the following ranges for each age group:
- Adult: BMI values between 18.5 and 24.9
- Senior: BMI values above 24.9

Using this information, we can generate the dictionary as follows:

```json
{
	"Adult": [18.7, 21.3, 22.9, 23.6, 24.0],
	"Senior": [25.4, 26.8, 27.2, 29.1, 31.5]
}
```

The values provided in the lists are just examples of typical BMXBMI values for each age group. The actual values may vary depending on the dataset being analyzed.