condition mean min max ZT0-3 2.63416 2.219285 3.3371500000000003 ZT4-7 1.4916749999999999 1.4916749999999999 1.4916749999999999 ZT8-11 2.010115 2.010115 2.010115 ZT12-15 2.0062275 1.870845 2.14161 ZT16-19 2.2564599999999997 2.2564599999999997 2.2564599999999997 ZT20-23 2.606535 2.606535 2.606535