condition mean min max ZT0-3 5.65 5.65 5.65 ZT4-7 2.7 2.7 2.7 ZT8-11 5.75 5.75 5.75 ZT12-15 16.95 16.95 16.95 ZT16-19 20.700000000000003 20.700000000000003 20.700000000000003 ZT20-23 6.0 6.0 6.0