condition mean min max ZT0-3 2.9000000000000004 2.9000000000000004 2.9000000000000004 ZT4-7 1.1 1.1 1.1 ZT8-11 2.1 2.1 2.1 ZT12-15 3.4 3.4 3.4 ZT16-19 13.5 13.5 13.5 ZT20-23 4.699999999999999 4.699999999999999 4.699999999999999