condition mean min max ZT0-3 1.2559125 0.672705 1.858555 ZT4-7 2.01935 2.01935 2.01935 ZT8-11 1.307715 1.307715 1.307715 ZT12-15 3.6460799999999995 3.34467 3.9474899999999997 ZT16-19 3.35488 3.35488 3.35488 ZT20-23 3.265135 3.265135 3.265135