condition mean min max ZT0-3 9.75 9.75 9.75 ZT4-7 41.3 41.3 41.3 ZT8-11 11.7 11.7 11.7 ZT12-15 18.900000000000002 18.900000000000002 18.900000000000002 ZT16-19 38.15 38.15 38.15 ZT20-23 33.0 33.0 33.0