condition mean min max ZT0-3 2.5591 2.51067 2.6075299999999997 ZT4-7 1.81453 1.81453 1.81453 ZT8-11 2.3615 2.3615 2.3615 ZT12-15 0 0 0 ZT16-19 2.500535 2.500535 2.500535 ZT20-23 2.19293 2.19293 2.19293