condition mean min max ZT0-3 16.869467 16.869467 16.869467 ZT4-7 23.5082625 23.5082625 23.5082625 ZT8-11 27.2743425 27.2743425 27.2743425 ZT12-15 26.871576 26.871576 26.871576 ZT16-19 18.365747499999998 18.365747499999998 18.365747499999998 ZT20-23 13.724154500000001 13.724154500000001 13.724154500000001