condition mean min max ZT0-3 1.642605 1.642605 1.642605 ZT4-7 1.14478 1.14478 1.14478 ZT8-11 2.39614 2.39614 2.39614 ZT12-15 2.987885 2.987885 2.987885 ZT16-19 2.9552750000000003 2.9552750000000003 2.9552750000000003 ZT20-23 2.68346 2.68346 2.68346