Based on prior knowledge, the duration feature could be an important factor in determining whether a person receives credit or not. Generally, longer durations may indicate a higher likelihood of receiving credit, as individuals with longer durations may have more stable financial situations and are more likely to repay their debts.

Here is the analysis of the relationship between the duration feature and the task:

- For the target class "yes" (person receives credit): 
  - Possible duration values: 12, 18, 24, 30, 36 (months)
  - Typically, individuals who receive credit tend to have durations between 12 and 36 months.

- For the target class "no" (person does not receive credit): 
  - Possible duration values: 6, 9, 15, 21, 27 (months)
  - Typically, individuals who do not receive credit tend to have durations between 6 and 27 months.

Based on this analysis, here is the dictionary:

```json
{
	"yes": [12.0, 18.0, 24.0, 30.0, 36.0],
	"no": [6.0, 9.0, 15.0, 21.0, 27.0]
}
```
Please note that these values are just examples and may vary depending on the specific dataset and context.