condition mean min max ZT0-3 6.335425000000001 5.590765 7.080085 ZT4-7 11.3871 11.3871 11.3871 ZT8-11 11.15203 11.15203 11.15203 ZT12-15 0 0 0 ZT16-19 10.037555000000001 10.037555000000001 10.037555000000001 ZT20-23 7.22815 7.22815 7.22815