condition mean min max ZT0-3 2.1256266666666668 2.1256266666666668 2.1256266666666668 ZT4-7 1.7771599999999999 1.7771599999999999 1.7771599999999999 ZT8-11 2.9032299999999998 2.9032299999999998 2.9032299999999998 ZT12-15 2.9734249999999998 2.9734249999999998 2.9734249999999998 ZT16-19 3.4617 3.4617 3.4617 ZT20-23 3.0481 3.0481 3.0481