condition mean min max ZT0-3 14.984206 14.984206 14.984206 ZT4-7 18.114705999999998 18.114705999999998 18.114705999999998 ZT8-11 21.283474499999997 21.283474499999997 21.283474499999997 ZT12-15 17.672107 17.672107 17.672107 ZT16-19 17.31317 17.31317 17.31317 ZT20-23 15.513359999999999 15.513359999999999 15.513359999999999