Analysis:

To analyze the relationship between the feature "Repetition" and the task of predicting the grain yield of a soybean cultivar as low or high, we need to consider our prior knowledge about the feature and its potential impact on the target variable.

The feature "Repetition" is a numeric variable that indicates the number of times a particular soybean cultivar has been repeated in the dataset. The repetition of a cultivar may have an impact on its yield. However, it is important to note that without additional information or context, it is difficult to determine the specific relationship between "Repetition" and grain yield.

Creating the dictionary:

Without specific information about the relationship between "Repetition" and grain yield, we can use our prior knowledge to provide a general analysis of the feature. Based on this analysis, we will create a dictionary that includes five typical Repetition values for each target class ('low' and 'high').

```json
{
	"low": [1.0, 2.0, 3.0, 4.0, 5.0],
	"high": [1.0, 2.0, 3.0, 4.0, 5.0]
}
```

Please note that these values are just examples and may not accurately represent the relationship between "Repetition" and grain yield without further domain-specific information.