Based on prior knowledge, AST_BLOOD is the measurement of Serum AsAT content. The range of values for AST_BLOOD may vary based on the specific unit of measurement (IU/L or U/L) used in the dataset.

To analyze the relationship between AST_BLOOD and the presence of chronic heart failure (CHF), we'll examine the typical ranges of AST_BLOOD values for patients with and without CHF.

Here's a dictionary showing the possible values of AST_BLOOD for each target class:

```json
{
    "no": [35.0, 41.2, 39.8, 42.5, 38.1],
    "yes": [48.9, 57.3, 50.6, 53.2, 55.1]
}
```

Please note that the above values are just hypothetical examples and may not reflect the actual values in the dataset. The dictionary provides five typical AST_BLOOD values for each target class ('no' and 'yes') for analyzing the presence of chronic heart failure.