condition mean min max ZT0-3 2.4830083333333333 2.0082 2.94246 ZT4-7 1.9824 1.9824 1.9824 ZT8-11 2.576745 2.576745 2.576745 ZT12-15 4.3899 4.1936 4.5862 ZT16-19 6.015485 6.015485 6.015485 ZT20-23 5.0727899999999995 5.0727899999999995 5.0727899999999995