condition mean min max ZT0-3 8.563086 8.563086 8.563086 ZT4-7 8.6757995 8.6757995 8.6757995 ZT8-11 7.7687425 7.7687425 7.7687425 ZT12-15 7.5851965 7.5851965 7.5851965 ZT16-19 7.8653865 7.8653865 7.8653865 ZT20-23 7.7804015 7.7804015 7.7804015