condition mean min max ZT0-3 3.7421266666666666 2.88506 4.817685 ZT4-7 5.014279999999999 5.014279999999999 5.014279999999999 ZT8-11 5.617395 5.617395 5.617395 ZT12-15 10.00685 9.749995 10.263705 ZT16-19 9.4779 9.4779 9.4779 ZT20-23 7.220605 7.220605 7.220605