condition mean min max ZT0-3 10.463935 10.463935 10.463935 ZT4-7 7.080245 7.080245 7.080245 ZT8-11 2.702245 2.702245 2.702245 ZT12-15 5.26357 5.26357 5.26357 ZT16-19 20.7608 20.7608 20.7608 ZT20-23 14.1833 14.1833 14.1833