condition mean min max ZT0-3 4.628425 4.628425 4.628425 ZT4-7 3.827655 3.827655 3.827655 ZT8-11 4.046245 4.046245 4.046245 ZT12-15 5.094105 5.094105 5.094105 ZT16-19 6.326775 6.326775 6.326775 ZT20-23 5.137455 5.137455 5.137455