condition mean min max ZT0-3 2.6 2.6 2.6 ZT4-7 10.6 10.6 10.6 ZT8-11 6.0 6.0 6.0 ZT12-15 10.1 10.1 10.1 ZT16-19 31.700000000000003 31.700000000000003 31.700000000000003 ZT20-23 2.5 2.5 2.5