condition mean min max ZT0-3 6.672713333333333 3.58787 9.74037 ZT4-7 4.401165 4.401165 4.401165 ZT8-11 5.05433 5.05433 5.05433 ZT12-15 3.42406 1.648445 5.199675 ZT16-19 4.77175 4.77175 4.77175 ZT20-23 9.22915 9.22915 9.22915