condition mean min max ZT0-3 3.276116666666667 3.24498 3.308985 ZT4-7 2.87273 2.87273 2.87273 ZT8-11 2.48501 2.48501 2.48501 ZT12-15 3.6273475 3.17644 4.078255 ZT16-19 3.8093250000000003 3.8093250000000003 3.8093250000000003 ZT20-23 4.132795 4.132795 4.132795