condition mean min max ZT0-3 3.8955249999999997 3.6672649999999996 4.123785 ZT4-7 3.94062 3.94062 3.94062 ZT8-11 14.9041 14.9041 14.9041 ZT12-15 0 0 0 ZT16-19 9.123750000000001 9.123750000000001 9.123750000000001 ZT20-23 7.331389999999999 7.331389999999999 7.331389999999999