condition mean min max ZT0-3 2.1161675 1.952295 2.28004 ZT4-7 2.3807150000000004 2.3807150000000004 2.3807150000000004 ZT8-11 0.936385 0.936385 0.936385 ZT12-15 0 0 0 ZT16-19 1.7165 1.7165 1.7165 ZT20-23 2.633005 2.633005 2.633005