condition mean min max ZT0-3 9.407407 9.407407 9.407407 ZT4-7 8.7459335 8.7459335 8.7459335 ZT8-11 8.35283 8.35283 8.35283 ZT12-15 9.835986 9.835986 9.835986 ZT16-19 9.546079500000001 9.546079500000001 9.546079500000001 ZT20-23 9.5394055 9.5394055 9.5394055