Based on prior knowledge, it is likely that the duration of a credit can be an important factor in determining whether a person receives credit or not. Generally, banks may prefer shorter duration loans as they are less risky. 

To analyze the relationship between the duration feature and the task of whether a person receives credit or not, we can compare the distribution of duration values for both target classes ('yes' and 'no'). 

Based on this analysis, the dictionary with the requested format can be generated as follows:

```json
{
	"yes": [6.0, 9.0, 12.0, 15.0, 18.0],
	"no": [24.0, 36.0, 48.0, 60.0, 72.0]
}
```

These values represent typical durations for each target class. Please note that the specific values are just examples and it would be necessary to analyze the actual data to provide accurate typical duration values.