condition mean min max ZT0-3 20.09915 20.09915 20.09915 ZT4-7 15.7743 15.7743 15.7743 ZT8-11 7.689545 7.689545 7.689545 ZT12-15 8.591155 8.591155 8.591155 ZT16-19 14.95755 14.95755 14.95755 ZT20-23 23.0167 23.0167 23.0167