Program: 69661
Project: 69661
Buggy source:
public Series getMultipleChoice(Item item,StatisticsItem itemStats){
  List<StatisticChoiceOption> statisticResponses=qtiStatisticsManager.getNumOfRightAnsweredMultipleChoice(item,resourceResult.getSearchParams());
  BarSeries d1=new BarSeries("String_Node_Str");
  BarSeries d2=new BarSeries("String_Node_Str");
  BarSeries d3=new BarSeries("String_Node_Str");
  String mediaBaseURL=resourceResult.getMediaBaseURL();
  boolean survey=QTIType.survey.equals(resourceResult.getType());
  int numOfParticipants=resourceResult.getQTIStatisticAssessment().getNumOfParticipants();
  int notAnswered=numOfParticipants - (itemStats == null ? 0 : itemStats.getNumOfResults());
  int i=0;
  List<ResponseInfos> responseInfos=new ArrayList<>();
  for (  StatisticChoiceOption statisticResponse : statisticResponses) {
    Response response=statisticResponse.getResponse();
    float points=response.getPoints();
    double answersPerAnswerOption=statisticResponse.getCount();
    double rightA;
    double wrongA;
    if (points >= 0f) {
      rightA=answersPerAnswerOption;
      wrongA=numOfParticipants - notAnswered - answersPerAnswerOption;
    }
 else {
      rightA=numOfParticipants - notAnswered - answersPerAnswerOption;
      wrongA=answersPerAnswerOption;
    }
    String label=Integer.toString(++i);
    d1.add(rightA,label);
    d2.add(wrongA,label);
    d3.add(notAnswered,label);
    String text=response.getContent().renderAsHtml(mediaBaseURL);
    Float pointsObj=survey ? null : points;
    responseInfos.add(new ResponseInfos(label,text,pointsObj,true,survey));
  }
  List<BarSeries> serieList=new ArrayList<>(3);
  serieList.add(d1);
  if (!survey) {
    serieList.add(d2);
    serieList.add(d3);
  }
  Series series=new Series(serieList,responseInfos,numOfParticipants);
  series.setChartType(survey ? BAR_ANSWERED : BAR_CORRECT_WRONG_NOT);
  series.setItemCss(getCssClass(item));
  return series;
}

Fixed version (ground truth):
public Series getMultipleChoice(Item item,StatisticsItem itemStats){
  List<StatisticChoiceOption> statisticResponses=qtiStatisticsManager.getNumOfRightAnsweredMultipleChoice(item,resourceResult.getSearchParams());
  BarSeries d1=new BarSeries("String_Node_Str");
  BarSeries d2=new BarSeries("String_Node_Str");
  BarSeries d3=new BarSeries("String_Node_Str");
  String mediaBaseURL=resourceResult.getMediaBaseURL();
  boolean survey=QTIType.survey.equals(resourceResult.getType());
  int numOfParticipants=resourceResult.getQTIStatisticAssessment().getNumOfParticipants();
  int notAnswered=numOfParticipants - (itemStats == null ? 0 : itemStats.getNumOfResults());
  int i=0;
  List<ResponseInfos> responseInfos=new ArrayList<>();
  for (  StatisticChoiceOption statisticResponse : statisticResponses) {
    Response response=statisticResponse.getResponse();
    float points=response.getPoints();
    double answersPerAnswerOption=statisticResponse.getCount();
    double rightA;
    double wrongA;
    if (points >= 0f) {
      rightA=answersPerAnswerOption;
      wrongA=numOfParticipants - notAnswered - answersPerAnswerOption;
    }
 else {
      rightA=numOfParticipants - notAnswered - answersPerAnswerOption;
      wrongA=answersPerAnswerOption;
    }
    String label=Integer.toString(++i);
    d1.add(rightA,label);
    d2.add(wrongA,label);
    d3.add(notAnswered,label);
    String text=response.getContent().renderAsHtml(mediaBaseURL);
    Float pointsObj=survey ? null : points;
    responseInfos.add(new ResponseInfos(label,text,pointsObj,(points > 0f),survey));
  }
  List<BarSeries> serieList=new ArrayList<>(3);
  serieList.add(d1);
  if (!survey) {
    serieList.add(d2);
    serieList.add(d3);
  }
  Series series=new Series(serieList,responseInfos,numOfParticipants);
  series.setChartType(survey ? BAR_ANSWERED : BAR_CORRECT_WRONG_NOT);
  series.setItemCss(getCssClass(item));
  return series;
}