condition mean min max ZT0-3 2.592496666666667 1.28578 3.56109 ZT4-7 0.9144345 0.9144345 0.9144345 ZT8-11 1.957695 1.957695 1.957695 ZT12-15 3.6636125 3.231855 4.09537 ZT16-19 3.71375 3.71375 3.71375 ZT20-23 4.985315 4.985315 4.985315