condition mean min max ZT0-3 3.715555 3.715555 3.715555 ZT4-7 6.289745 6.289745 6.289745 ZT8-11 2.9398150000000003 2.9398150000000003 2.9398150000000003 ZT12-15 2.68249 2.68249 2.68249 ZT16-19 4.60712 4.60712 4.60712 ZT20-23 3.68959 3.68959 3.68959