condition mean min max ZT0-3 2.5622416666666665 2.3149949999999997 2.965605 ZT4-7 3.738415 3.738415 3.738415 ZT8-11 4.391765 4.391765 4.391765 ZT12-15 3.7170724999999996 2.892495 4.54165 ZT16-19 2.618525 2.618525 2.618525 ZT20-23 2.3173950000000003 2.3173950000000003 2.3173950000000003