condition mean min max ZT0-3 5.3313825 4.72422 5.9385449999999995 ZT4-7 6.67016 6.67016 6.67016 ZT8-11 5.47173 5.47173 5.47173 ZT12-15 0 0 0 ZT16-19 7.22985 7.22985 7.22985 ZT20-23 8.398115 8.398115 8.398115