condition mean min max ZT0-3 3.901445 1.8148399999999998 5.785595000000001 ZT4-7 1.54215 1.54215 1.54215 ZT8-11 3.03728 3.03728 3.03728 ZT12-15 5.5055825 5.0009999999999994 6.010165000000001 ZT16-19 5.621924999999999 5.621924999999999 5.621924999999999 ZT20-23 7.61403 7.61403 7.61403