condition mean min max ZT0-3 1.1623121666666667 0.1821065 2.96363 ZT4-7 0.52071 0.52071 0.52071 ZT8-11 3.0691995000000003 3.0691995000000003 3.0691995000000003 ZT12-15 2.8669425000000004 1.902745 3.8311400000000004 ZT16-19 5.388014999999999 5.388014999999999 5.388014999999999 ZT20-23 2.962565 2.962565 2.962565