condition mean min max ZT0-3 2.7024533333333336 2.58268 2.8896550000000003 ZT4-7 4.006235 4.006235 4.006235 ZT8-11 3.0114400000000003 3.0114400000000003 3.0114400000000003 ZT12-15 4.3896275000000005 3.87743 4.9018250000000005 ZT16-19 3.87143 3.87143 3.87143 ZT20-23 3.480195 3.480195 3.480195