condition mean min max ZT0-3 51.900000000000006 51.900000000000006 51.900000000000006 ZT4-7 7.5 7.5 7.5 ZT8-11 18.85 18.85 18.85 ZT12-15 30.95 30.95 30.95 ZT16-19 59.1 59.1 59.1 ZT20-23 75.15 75.15 75.15