code: public FlatDataList getYColumn() {
          FlatDataList flatDataList = new FlatDataList();
  
          for(Record r : values()) {
              flatDataList.add(r.getY());
          }
  
          return flatDataList;
      }
docs: It extracts the values of the response variables from all observations and
  stores them into an FlatDataList.
  
  @return