condition mean min max ZT0-3 17.081899 17.081899 17.081899 ZT4-7 15.8631155 15.8631155 15.8631155 ZT8-11 12.2716675 12.2716675 12.2716675 ZT12-15 14.0743785 14.0743785 14.0743785 ZT16-19 13.12793 13.12793 13.12793 ZT20-23 17.492002499999998 17.492002499999998 17.492002499999998