condition mean min max ZT0-3 10.511695 10.511695 10.511695 ZT4-7 8.555205 8.555205 8.555205 ZT8-11 16.9785 16.9785 16.9785 ZT12-15 21.89615 21.89615 21.89615 ZT16-19 37.5057 37.5057 37.5057 ZT20-23 14.2166 14.2166 14.2166