condition mean min max ZT0-3 2.4747733333333333 1.802545 3.10521 ZT4-7 4.0302500000000006 4.0302500000000006 4.0302500000000006 ZT8-11 3.430775 3.430775 3.430775 ZT12-15 4.9255075 3.919965 5.93105 ZT16-19 3.9910300000000003 3.9910300000000003 3.9910300000000003 ZT20-23 4.07291 4.07291 4.07291