condition mean min max ZT0-3 9.337282 9.337282 9.337282 ZT4-7 10.2704345 10.2704345 10.2704345 ZT8-11 8.896902 8.896902 8.896902 ZT12-15 8.9222275 8.9222275 8.9222275 ZT16-19 8.962653 8.962653 8.962653 ZT20-23 8.7677445 8.7677445 8.7677445