condition mean min max ZT0-3 17.825797 17.825797 17.825797 ZT4-7 19.7615825 19.7615825 19.7615825 ZT8-11 19.806203500000002 19.806203500000002 19.806203500000002 ZT12-15 25.2931855 25.2931855 25.2931855 ZT16-19 18.500532999999997 18.500532999999997 18.500532999999997 ZT20-23 18.6094175 18.6094175 18.6094175