condition mean min max ZT0-3 17.439925 14.893249999999998 19.9866 ZT4-7 15.6356 15.6356 15.6356 ZT8-11 33.2526 33.2526 33.2526 ZT12-15 0 0 0 ZT16-19 41.6258 41.6258 41.6258 ZT20-23 24.537149999999997 24.537149999999997 24.537149999999997