condition mean min max ZT0-3 3.735106666666667 3.09706 4.167095 ZT4-7 3.5695050000000004 3.5695050000000004 3.5695050000000004 ZT8-11 3.45152 3.45152 3.45152 ZT12-15 4.1579 3.958215 4.357585 ZT16-19 3.908645 3.908645 3.908645 ZT20-23 4.39701 4.39701 4.39701