condition mean min max ZT0-3 8.603564 8.603564 8.603564 ZT4-7 8.544988 8.544988 8.544988 ZT8-11 8.7223555 8.7223555 8.7223555 ZT12-15 8.497987 8.497987 8.497987 ZT16-19 8.007886 8.007886 8.007886 ZT20-23 9.07958 9.07958 9.07958