condition mean min max ZT0-3 2.39694 2.39694 2.39694 ZT4-7 2.19867 2.19867 2.19867 ZT8-11 3.01634 3.01634 3.01634 ZT12-15 2.6445 2.6445 2.6445 ZT16-19 2.25208 2.25208 2.25208 ZT20-23 1.7653999999999999 1.7653999999999999 1.7653999999999999