Based on the given feature description and task, my analysis would involve examining the likely values of feature LBXGLT for the target classes 'Adult' and 'Senior' in order to determine their appropriate ranges.

To create the dictionary, I will assign the values for feature LBXGLT that are typical for the 'Adult' age group to the key "Adult", and assign the values typical for the 'Senior' age group to the key "Senior".

Here is the requested dictionary:

```json
{
    "Adult": [0.5, 1.2, 2.7, 3.4, 4.6],
    "Senior": [5.8, 6.9, 7.2, 8.1, 9.3]
}
```

Please note that these example values are placeholders and should be replaced with real values based on a thorough analysis of the relationship between feature LBXGLT and the target variable.