condition mean min max ZT0-3 2.8691225 2.79735 2.9408950000000003 ZT4-7 3.3327 3.3327 3.3327 ZT8-11 2.05946 2.05946 2.05946 ZT12-15 0 0 0 ZT16-19 3.269525 3.269525 3.269525 ZT20-23 3.659915 3.659915 3.659915