condition mean min max ZT0-3 2.5312653333333333 1.2753510000000001 3.1599 ZT4-7 2.061555 2.061555 2.061555 ZT8-11 1.75789 1.75789 1.75789 ZT12-15 2.634615 2.373755 2.8954750000000002 ZT16-19 3.5719000000000003 3.5719000000000003 3.5719000000000003 ZT20-23 4.7361699999999995 4.7361699999999995 4.7361699999999995