condition mean min max ZT0-3 6.347995 4.371425 8.324565 ZT4-7 4.249885 4.249885 4.249885 ZT8-11 2.558535 2.558535 2.558535 ZT12-15 0 0 0 ZT16-19 8.18036 8.18036 8.18036 ZT20-23 6.477679999999999 6.477679999999999 6.477679999999999