code: public static DiscreteFactor getMeans(DiscreteFactor featureFactor, int featureVariableNum) {
      return getMeans(Arrays.asList(featureFactor), featureVariableNum);
    }
docs: Gets the mean value of each assignment to {@code featureVariableNum} in
  {@code featureFactor}.
  
  @param featureFactor
  @param featureVariableNum
  @return