condition mean min max ZT0-3 6.7179 6.7179 6.7179 ZT4-7 4.808455 4.808455 4.808455 ZT8-11 4.093555 4.093555 4.093555 ZT12-15 5.67303 5.67303 5.67303 ZT16-19 9.04003 9.04003 9.04003 ZT20-23 8.046615 8.046615 8.046615