Based on my prior knowledge, I can analyze the relationship between the "duration" feature and the task of determining whether the client subscribes to a term deposit or not.

Typically, the "duration" feature represents the duration of the last contact with the client. A longer duration may indicate a more engaging or positive conversation, which could potentially increase the likelihood of the client subscribing to a term deposit. However, it is important to note that this is a generic analysis and the relationship may vary depending on the specific dataset and context.

Here is the dictionary with typical duration values for each target class:

```json
{
	"no": [80.0, 120.0, 150.0, 180.0, 200.0],
	"yes": [240.0, 280.0, 320.0, 360.0, 400.0]
}
```

Please note that these typical duration values are based on generic assumptions and may not accurately reflect the specific dataset being analyzed. It is advisable to perform a thorough analysis on the dataset to obtain more accurate and context-specific duration ranges for each target class.