condition mean min max ZT0-3 3.584531666666667 1.92869 4.6592 ZT4-7 1.610665 1.610665 1.610665 ZT8-11 2.34643 2.34643 2.34643 ZT12-15 4.39682 3.61327 5.18037 ZT16-19 5.00469 5.00469 5.00469 ZT20-23 6.7631250000000005 6.7631250000000005 6.7631250000000005