condition mean min max ZT0-3 6.64901 6.64901 6.64901 ZT4-7 2.13545 2.13545 2.13545 ZT8-11 2.42321 2.42321 2.42321 ZT12-15 7.011655 7.011655 7.011655 ZT16-19 12.533249999999999 12.533249999999999 12.533249999999999 ZT20-23 11.03505 11.03505 11.03505