Based on the given feature description, the feature PAQ605 represents whether the respondent engages in moderate or vigorous-intensity physical activities in a typical week. The values for this feature are represented numerically, with 1 indicating that the respondent takes part in weekly moderate or vigorous-intensity physical activity, and 2 indicating that they do not.

To analyze the relationship between the feature PAQ605 and the target variable (age group), we can make use of our prior knowledge.

Considering that the task is to predict whether a person belongs to the senior age group or not, we can assume that senior individuals are less likely to engage in vigorous-intensity physical activities compared to non-seniors. Therefore, we can expect a higher proportion of values as 2 (indicating no engagement in physical activity) for the seniors.

Based on this analysis, let's 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": [1.0, 1.0, 1.0, 2.0, 2.0]
}
```

In the above dictionary, the "Adult" key represents the target class for non-senior individuals, and the corresponding values [1.0, 1.0, 1.0, 1.0, 1.0] indicate that they are more likely to engage in moderate or vigorous-intensity physical activities.

Similarly, the "Senior" key represents the target class for senior individuals, and the corresponding values [1.0, 1.0, 1.0, 2.0, 2.0] suggest that seniors are less likely to engage in physical activities, with a higher proportion of values as 2.0 indicating no engagement in such activities.

Please note that the values provided in the dictionary above are example values, and you can replace them with actual representative values from your dataset.