condition mean min max ZT0-3 6.94684 6.0017 7.766769999999999 ZT4-7 5.873760000000001 5.873760000000001 5.873760000000001 ZT8-11 8.45922 8.45922 8.45922 ZT12-15 7.189615 6.89804 7.48119 ZT16-19 7.8906600000000005 7.8906600000000005 7.8906600000000005 ZT20-23 9.696165 9.696165 9.696165