condition mean min max ZT0-3 3.100486666666667 2.04554 4.340205 ZT4-7 1.20248 1.20248 1.20248 ZT8-11 1.446915 1.446915 1.446915 ZT12-15 4.138555 3.25339 5.02372 ZT16-19 3.85349 3.85349 3.85349 ZT20-23 4.60506 4.60506 4.60506