condition mean min max ZT0-3 15.356175 14.725950000000001 15.9864 ZT4-7 6.929765 6.929765 6.929765 ZT8-11 7.085975 7.085975 7.085975 ZT12-15 0 0 0 ZT16-19 12.8842 12.8842 12.8842 ZT20-23 12.8387 12.8387 12.8387