condition mean min max ZT0-3 8.0 8.0 8.0 ZT4-7 4.5 4.5 4.5 ZT8-11 3.5999999999999996 3.5999999999999996 3.5999999999999996 ZT12-15 11.15 11.15 11.15 ZT16-19 9.1 9.1 9.1 ZT20-23 6.3 6.3 6.3