condition mean min max ZT0-3 4.299976666666667 4.131945 4.54493 ZT4-7 3.32924 3.32924 3.32924 ZT8-11 2.869975 2.869975 2.869975 ZT12-15 5.168695 3.895265 6.442125 ZT16-19 5.560805 5.560805 5.560805 ZT20-23 5.7115100000000005 5.7115100000000005 5.7115100000000005