condition mean min max ZT0-3 12.158975 10.9668 13.35115 ZT4-7 3.665595 3.665595 3.665595 ZT8-11 3.4017500000000003 3.4017500000000003 3.4017500000000003 ZT12-15 0 0 0 ZT16-19 4.18639 4.18639 4.18639 ZT20-23 7.85206 7.85206 7.85206