condition mean min max ZT0-3 2.876706 2.876706 2.876706 ZT4-7 1.077699 1.077699 1.077699 ZT8-11 0.377105 0.377105 0.377105 ZT12-15 0.9266885 0.9266885 0.9266885 ZT16-19 1.415565 1.415565 1.415565 ZT20-23 2.5515705 2.5515705 2.5515705