Analysis:

To determine the appropriate ranges of values for LBXGLT in predicting the age group, we can use our prior knowledge of age-related health conditions and considerations.

LBXGLT stands for "Glucose - Oral Glucose Tolerance (mg/dL)" and is a measure of glucose levels during an oral glucose tolerance test. This test is commonly used to assess the body's ability to metabolize glucose and is often used as a diagnostic tool for diabetes.

Based on our understanding, glucose levels can vary with age, and higher glucose levels are generally associated with age-related health conditions such as diabetes. As individuals age, their body's ability to regulate glucose levels may decline, resulting in higher glucose levels.

Therefore, we can hypothesize that higher LBXGLT values may be more indicative of the senior age group.

Dictionary:

Based on the analysis above, we can create the following dictionary:

```json
{
	"Adult": [100.2, 108.5, 112.7, 95.4, 98.6],
	"Senior": [120.3, 128.1, 132.9, 115.6, 121.8]
}
```

This dictionary represents five typical LBXGLT values for each target class. The LBXGLT values are presented as floats in the lists. Please note that these values are just examples and may not reflect the actual distribution of LBXGLT values for each age group. A more comprehensive analysis would require a larger dataset and statistical techniques to determine the appropriate ranges.