condition mean min max ZT0-3 9.607642 9.607642 9.607642 ZT4-7 9.6291285 9.6291285 9.6291285 ZT8-11 8.9165615 8.9165615 8.9165615 ZT12-15 9.101833 9.101833 9.101833 ZT16-19 9.734200000000001 9.734200000000001 9.734200000000001 ZT20-23 9.5484395 9.5484395 9.5484395