condition mean min max ZT0-3 0.8500000000000001 0.8500000000000001 0.8500000000000001 ZT4-7 4.2 4.2 4.2 ZT8-11 1.7999999999999998 1.7999999999999998 1.7999999999999998 ZT12-15 1.0499999999999998 1.0499999999999998 1.0499999999999998 ZT16-19 1.5 1.5 1.5 ZT20-23 1.55 1.55 1.55