condition mean min max ZT0-3 28.0917649825 26.237538954999998 29.94599101 ZT4-7 26.280201965 21.87181715 30.68858678 ZT8-11 22.484035875 21.26410562 23.70396613 ZT12-15 34.707352650000004 31.236393363333335 38.17831193666667 ZT16-19 23.314996365 19.33233102 27.29766171 ZT20-23 17.80438781666667 16.35017621 19.258599423333333