condition mean min max ZT0-3 3.4644500000000003 3.4644500000000003 3.4644500000000003 ZT4-7 1.888555 1.888555 1.888555 ZT8-11 2.80236 2.80236 2.80236 ZT12-15 6.98579 6.98579 6.98579 ZT16-19 2.66633 2.66633 2.66633 ZT20-23 6.273070000000001 6.273070000000001 6.273070000000001