condition mean min max ZT0-3 8.803668 8.803668 8.803668 ZT4-7 8.5345765 8.5345765 8.5345765 ZT8-11 11.6386635 11.6386635 11.6386635 ZT12-15 10.715396 10.715396 10.715396 ZT16-19 15.0025495 15.0025495 15.0025495 ZT20-23 13.306614499999998 13.306614499999998 13.306614499999998