condition mean min max ZT0-3 6.94082 6.94082 6.94082 ZT4-7 7.18825 7.18825 7.18825 ZT8-11 1.45598 1.45598 1.45598 ZT12-15 8.89105 8.89105 8.89105 ZT16-19 3.13096 3.13096 3.13096 ZT20-23 3.894375 3.894375 3.894375