condition mean min max ZT0-3 2.75 2.75 2.75 ZT4-7 2.0 2.0 2.0 ZT8-11 4.050000000000001 4.050000000000001 4.050000000000001 ZT12-15 2.35 2.35 2.35 ZT16-19 1.75 1.75 1.75 ZT20-23 2.5999999999999996 2.5999999999999996 2.5999999999999996