condition mean min max ZT0-3 2.088191 1.456037 2.720345 ZT4-7 4.20873 4.20873 4.20873 ZT8-11 4.36061 4.36061 4.36061 ZT12-15 0 0 0 ZT16-19 2.5419864999999997 2.5419864999999997 2.5419864999999997 ZT20-23 4.322295 4.322295 4.322295