condition mean min max ZT0-3 18.981698 18.981698 18.981698 ZT4-7 18.0707855 18.0707855 18.0707855 ZT8-11 15.1582095 15.1582095 15.1582095 ZT12-15 18.420412499999998 18.420412499999998 18.420412499999998 ZT16-19 13.864475500000001 13.864475500000001 13.864475500000001 ZT20-23 13.136836500000001 13.136836500000001 13.136836500000001