condition mean min max ZT0-3 5.943095 5.943095 5.943095 ZT4-7 3.460565 3.460565 3.460565 ZT8-11 4.1558 4.1558 4.1558 ZT12-15 8.067145 8.067145 8.067145 ZT16-19 10.652455 10.652455 10.652455 ZT20-23 8.829464999999999 8.829464999999999 8.829464999999999