condition mean min max ZT0-3 2.3217675 2.290515 2.35302 ZT4-7 2.5404549999999997 2.5404549999999997 2.5404549999999997 ZT8-11 3.19888 3.19888 3.19888 ZT12-15 0 0 0 ZT16-19 4.436920000000001 4.436920000000001 4.436920000000001 ZT20-23 3.98364 3.98364 3.98364