condition mean min max ZT0-3 3.5 3.5 3.5 ZT4-7 4.3 4.3 4.3 ZT8-11 14.700000000000001 14.700000000000001 14.700000000000001 ZT12-15 6.15 6.15 6.15 ZT16-19 4.45 4.45 4.45 ZT20-23 2.0999999999999996 2.0999999999999996 2.0999999999999996