condition mean min max ZT0-3 5.260095 5.260095 5.260095 ZT4-7 3.83332 3.83332 3.83332 ZT8-11 6.41751 6.41751 6.41751 ZT12-15 7.554074999999999 7.554074999999999 7.554074999999999 ZT16-19 7.097905 7.097905 7.097905 ZT20-23 6.355475 6.355475 6.355475