Based on the given feature PAQ605 and the task of predicting the person's age group, we can analyze the relationship between the feature and target using prior knowledge.

Since PAQ605 represents whether the respondent engages in moderate or vigorous-intensity physical activity in a typical week, we can assume that individuals who engage in such activities are more likely to be younger and fall into the "Adult" age group. On the other hand, individuals who do not participate in regular physical activities may be older and fall into the "Senior" age group.

Based on this analysis, we can create a dictionary with the possible values of feature PAQ605 for each target class:

```json
{
	"Adult": [1.0, 1.0, 1.0, 1.0, 1.0],  
	"Senior": [2.0, 2.0, 2.0, 2.0, 2.0]
}
```

In this case, we assume that the "Adult" age group is more likely to have values of 1.0 for PAQ605, indicating regular participation in moderate or vigorous-intensity physical activities. The "Senior" age group is more likely to have values of 2.0, indicating no participation in such activities.

Please note that the values presented here are just examples, and the actual data may have different ranges of values or patterns.