condition mean min max ZT0-3 2.898025 2.898025 2.898025 ZT4-7 2.6943900000000003 2.6943900000000003 2.6943900000000003 ZT8-11 2.1617699999999997 2.1617699999999997 2.1617699999999997 ZT12-15 2.18782 2.18782 2.18782 ZT16-19 3.17779 3.17779 3.17779 ZT20-23 2.9553000000000003 2.9553000000000003 2.9553000000000003