Based on my prior knowledge, blood insulin levels can vary depending on various factors such as age, body weight, and overall health. However, seniors may generally have higher blood insulin levels compared to non-seniors due to age-related changes in insulin production and sensitivity.

To analyze the relationship between the feature LBXIN (blood insulin levels) and the target task of predicting age group (senior or non-senior), we can examine typical LBXIN values for each target class.

Here is the dictionary detailing typical LBXIN values for each target class:

```json
{
	"Adult": [10.2, 12.4, 8.7, 9.9, 11.3], 
	"Senior": [14.6, 16.2, 13.8, 15.1, 17.9]
}
```

Please note that these values are hypothetical and provided for illustration purposes only. The actual LBXIN values and their ranges should be determined based on a comprehensive analysis of the dataset or domain knowledge.