condition mean min max ZT0-3 6489.436118 6489.436118 6489.436118 ZT4-7 6950.7658425 6950.7658425 6950.7658425 ZT8-11 7403.470476 7403.470476 7403.470476 ZT12-15 7107.21014 7107.21014 7107.21014 ZT16-19 7564.936854 7564.936854 7564.936854 ZT20-23 8030.333983500001 8030.333983500001 8030.333983500001