condition mean min max ZT0-3 2.1455033333333335 2.0946350000000002 2.19529 ZT4-7 1.995535 1.995535 1.995535 ZT8-11 3.4533000000000005 3.4533000000000005 3.4533000000000005 ZT12-15 4.2421375 3.75908 4.725194999999999 ZT16-19 4.190065 4.190065 4.190065 ZT20-23 3.2453000000000003 3.2453000000000003 3.2453000000000003