condition mean min max ZT0-3 17.082716666666666 15.33035 18.6167 ZT4-7 13.204999999999998 13.204999999999998 13.204999999999998 ZT8-11 14.68035 14.68035 14.68035 ZT12-15 27.596874999999997 26.7456 28.44815 ZT16-19 19.13855 19.13855 19.13855 ZT20-23 22.9623 22.9623 22.9623