condition mean min max ZT0-3 30.65 30.65 30.65 ZT4-7 40.8 40.8 40.8 ZT8-11 50.400000000000006 50.400000000000006 50.400000000000006 ZT12-15 61.2 61.2 61.2 ZT16-19 67.8 67.8 67.8 ZT20-23 19.65 19.65 19.65