condition mean min max ZT0-3 4.279115 4.279115 4.279115 ZT4-7 3.58493 3.58493 3.58493 ZT8-11 1.77502 1.77502 1.77502 ZT12-15 2.1821450000000002 2.1821450000000002 2.1821450000000002 ZT16-19 2.592705 2.592705 2.592705 ZT20-23 3.36365 3.36365 3.36365