To analyze the relationship between the feature "IFP" (plant height) and the target of high or low grain yield, we can use our prior knowledge of soybean cultivation to determine the appropriate ranges of values.

In general, the plant height can be an indicator of the plant's overall growth and vigor, which can affect grain yield. However, it is important to note that various factors such as genetic traits, growing conditions, and management practices can also impact grain yield.

For the purpose of this analysis, we will assume that higher plant heights generally indicate healthier and more robust plants, which may result in higher grain yield. Conversely, lower plant heights may indicate weaker or stressed plants, which may lead to lower grain yield.

Based on this analysis, we can create a dictionary with typical IFP values for each target class:

```json
{
	"low": [25.5, 26.0, 28.3, 29.1, 30.2],
	"high": [35.6, 37.2, 38.9, 40.1, 42.8]
}
```

Please note that these values are just examples and should be adjusted based on specific domain knowledge and available data.