code: protected boolean hasPlusMinusOneValues(StatementGroup statementGroup) {
  		if (statementGroup == null) {
  			return false;
  		}
  		for (Statement s : statementGroup) {
  			QuantityValue qv = (QuantityValue) s.getValue();
  			if (qv != null && isPlusMinusOneValue(qv)) {
  				return true;
  			}
  		}
  		return false;
  	}
docs: Checks if the given statement group contains at least one value of
  precision +/-1.
  
  @param statementGroup
  @return