validation of sigmas considers alternating row colors for bg color now

    bool convertSuccess = false;

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

    if (convertSuccess && sigma >= 0.0) {

      item->setBackground(Qt::white);

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

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

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

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

      }

      else {

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

      }

    }

    else {

      item->setBackground(Qt::red);