Based on my prior knowledge, I can analyze the relationship between the feature "nr_11" (Observing of arrhythmia in the anamnesis) and the task of determining if it shows chronic heart failure.

Since the feature "nr_11" refers to whether arrhythmia has been observed in the patient's medical history, it is reasonable to assume that patients with a positive history of arrhythmia may be more likely to show chronic heart failure. Therefore, I would expect the category "yes" in the feature "nr_11" to have a higher proportion of patients with chronic heart failure compared to the category "no".

To create the dictionary, I will go through the dataset and group the different values of the feature "nr_11" according to the corresponding target class of chronic heart failure. I will include only the distinct values of "nr_11" for each target class (both "yes" and "no") in the dictionary.

Here's the dictionary for the given feature and task:

```json
{
	"no": ["no"],  
	"yes": ["yes"]
}
```

Please note that I have included all possible values of feature "nr_11" for each target class, as requested in the format of the dictionary.