condition mean min max ZT0-3 18.642527 18.642527 18.642527 ZT4-7 20.301142499999997 20.301142499999997 20.301142499999997 ZT8-11 25.529747 25.529747 25.529747 ZT12-15 21.8616545 21.8616545 21.8616545 ZT16-19 24.342695499999998 24.342695499999998 24.342695499999998 ZT20-23 19.762656 19.762656 19.762656