condition mean min max ZT0-3 5.536503333333333 4.54831 6.546495 ZT4-7 6.507805 6.507805 6.507805 ZT8-11 8.513025 8.513025 8.513025 ZT12-15 8.2811775 7.67018 8.892175 ZT16-19 7.555055 7.555055 7.555055 ZT20-23 7.366075 7.366075 7.366075