condition mean min max ZT0-3 17.655871 17.655871 17.655871 ZT4-7 17.9286805 17.9286805 17.9286805 ZT8-11 18.7798005 18.7798005 18.7798005 ZT12-15 18.1934725 18.1934725 18.1934725 ZT16-19 18.336688 18.336688 18.336688 ZT20-23 18.0692145 18.0692145 18.0692145