Based on the given feature description, PAQ605 represents whether the respondent engages in moderate or vigorous-intensity sports, fitness, or recreational activities in a typical week. A value of 1 indicates that the respondent takes part in weekly moderate or vigorous-intensity physical activity, while a value of 2 indicates that they do not.

To analyze the relationship between PAQ605 and the target variable (age group: senior or non-senior), we can assume that individuals who engage in regular physical activity are likely to be in better health and have a higher likelihood of being non-senior. On the other hand, individuals who do not participate in physical activities might have a higher probability of being senior.

To create the dictionary, we need to find possible values of PAQ605 for each target class ('Adult' and 'Senior'). Here is the dictionary:

```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 can assume that individuals in the 'Adult' class are more likely to have a PAQ605 value of 1, indicating their engagement in physical activity. Conversely, individuals in the 'Senior' class are more likely to have a PAQ605 value of 2, representing their lack of participation in regular physical activity.

Please note that the dictionary provided above assumes that the relationship between PAQ605 and the target variable is straightforward, with a clear distinction between the possible values for each target class. This is a simplified example, and in a real-world scenario, additional analysis and modeling may be required to determine the precise relationship between the feature and target.