Based on prior knowledge, fasting blood sugar (FastingBS) is measured in mg/dl, and a value above 120 mg/dl is considered high, while a value of 120 mg/dl or below is considered normal.

To analyze the relationship between FastingBS and the presence of heart disease (the target variable), we can take a look at the typical ranges of FastingBS values for each target class.

Let's assume that the target variable is encoded as 'no' for no heart disease and 'yes' for heart disease.

Following is the dictionary with typical FastingBS values for each target class:

```json
{
    "no": [80.1, 85.5, 92.3, 105.9, 115.2], 
    "yes": [126.5, 135.4, 141.7, 150.8, 175.3]
}
```

In this case, for the 'no' class (no heart disease), the FastingBS values range from 80.1 to 115.2 mg/dl, and for the 'yes' class (heart disease), the FastingBS values range from 126.5 to 175.3 mg/dl. These ranges are just examples and should be considered typical for each target class.

Please note that there may be overlapping FastingBS values between the two target classes, and further analysis or statistical tests may be required to determine the significance of FastingBS in predicting heart disease.