protected function make_new_subq_stat_for($displaynumber, $slot, $subqid, $variant = null) {
        $slotstat = fullclone($this->for_subq($subqid, $variant));
        $slotstat->question->number = $this->for_slot($slot)->question->number;
        $slotstat->subqdisplayorder = $displaynumber;
        return $slotstat;
    }