condition mean min max ZT0-3 0.6331843333333333 0.3037655 0.979459 ZT4-7 0.5930475 0.5930475 0.5930475 ZT8-11 2.4434050000000003 2.4434050000000003 2.4434050000000003 ZT12-15 3.843925 3.59617 4.09168 ZT16-19 3.07915 3.07915 3.07915 ZT20-23 2.272315 2.272315 2.272315