protected void doPrintHeader() {
    if (m_Header.classAttribute().isNominal())
      if (m_OutputDistribution)
	append(" inst#     actual  predicted error distribution");
      else
	append(" inst#     actual  predicted error prediction");
    else
      append(" inst#     actual  predicted      error");
    
    if (m_Attributes != null) {
      append(" (");
      boolean first = true;
      for (int i = 0; i < m_Header.numAttributes(); i++) {
        if (i == m_Header.classIndex())
          continue;

        if (m_Attributes.isInRange(i)) {
          if (!first)
            append(",");
          append(m_Header.attribute(i).name());
          first = false;
        }
      }
      append(")");
    }
    
    append("\n");
  }