condition mean min max ZT0-3 4.5 4.5 4.5 ZT4-7 3.2 3.2 3.2 ZT8-11 20.75 20.75 20.75 ZT12-15 1.8499999999999999 1.8499999999999999 1.8499999999999999 ZT16-19 5.85 5.85 5.85 ZT20-23 12.05 12.05 12.05