condition mean min max ZT0-3 4.366865000000001 4.366865000000001 4.366865000000001 ZT4-7 2.13115 2.13115 2.13115 ZT8-11 1.702785 1.702785 1.702785 ZT12-15 1.8329499999999999 1.8329499999999999 1.8329499999999999 ZT16-19 2.42658 2.42658 2.42658 ZT20-23 3.7418 3.7418 3.7418