condition mean min max ZT0-3 2.404285 2.169185 2.6862649999999997 ZT4-7 1.5636100000000002 1.5636100000000002 1.5636100000000002 ZT8-11 2.55175 2.55175 2.55175 ZT12-15 4.146097500000001 4.111610000000001 4.180585000000001 ZT16-19 4.179075 4.179075 4.179075 ZT20-23 3.57614 3.57614 3.57614