FREE is now valid in a priori sigma items

      return;

    }

    // FREE is a valid value for the a priori sigma column

    int free = item->text().compare("FREE", Qt::CaseInsensitive);

    if (free == 0) {

      item->setText("FREE");

    }

    // Positive doubles are valid values for the a priori sigma column

    bool convertSuccess = false;

    double sigma = item->text().toDouble(&convertSuccess);

    if (convertSuccess && sigma >= 0.0) {

    if ((convertSuccess && sigma >= 0.0) || free == 0) {

      const QTableWidget *table = item->tableWidget();

      // Set background color depending on if the table has alternating row colors and is odd

      // Set background color depending on if the table has alternating row colors and row is odd

      if (table->alternatingRowColors() && item->row() % 2 != 0) {

        item->setBackground(table->palette().color(QPalette::AlternateBase));

      }