condition mean min max ZT0-3 10.551864 10.551864 10.551864 ZT4-7 12.5230565 12.5230565 12.5230565 ZT8-11 11.631557 11.631557 11.631557 ZT12-15 12.300420500000001 12.300420500000001 12.300420500000001 ZT16-19 8.8160845 8.8160845 8.8160845 ZT20-23 8.654583 8.654583 8.654583