condition mean min max ZT0-3 2.706545 2.706545 2.706545 ZT4-7 2.3283300000000002 2.3283300000000002 2.3283300000000002 ZT8-11 1.921935 1.921935 1.921935 ZT12-15 1.8639899999999998 1.8639899999999998 1.8639899999999998 ZT16-19 2.721505 2.721505 2.721505 ZT20-23 2.94874 2.94874 2.94874