condition mean min max ZT0-3 4.727790000000001 4.727790000000001 4.727790000000001 ZT4-7 3.2937399999999997 3.2937399999999997 3.2937399999999997 ZT8-11 3.6898549999999997 3.6898549999999997 3.6898549999999997 ZT12-15 8.40798 8.40798 8.40798 ZT16-19 11.07976 11.07976 11.07976 ZT20-23 6.612265 6.612265 6.612265