condition mean min max ZT0-3 1.58502 1.5615450000000002 1.612165 ZT4-7 1.41376 1.41376 1.41376 ZT8-11 1.8559199999999998 1.8559199999999998 1.8559199999999998 ZT12-15 2.63923 2.40642 2.87204 ZT16-19 2.47063 2.47063 2.47063 ZT20-23 3.0043699999999998 3.0043699999999998 3.0043699999999998