condition mean min max ZT0-3 23.6 23.6 23.6 ZT4-7 11.8 11.8 11.8 ZT8-11 39.8 39.8 39.8 ZT12-15 59.400000000000006 59.400000000000006 59.400000000000006 ZT16-19 54.85 54.85 54.85 ZT20-23 50.95 50.95 50.95