condition mean min max ZT0-3 18.984 18.1618 19.8062 ZT4-7 17.0751 17.0751 17.0751 ZT8-11 19.915399999999998 19.915399999999998 19.915399999999998 ZT12-15 0 0 0 ZT16-19 20.597450000000002 20.597450000000002 20.597450000000002 ZT20-23 18.8461 18.8461 18.8461