condition mean min max ZT0-3 0.157295 0.0 0.471885 ZT4-7 0.0 0.0 0.0 ZT8-11 0.0 0.0 0.0 ZT12-15 0.0 0.0 0.0 ZT16-19 0.0 0.0 0.0 ZT20-23 0.510935 0.510935 0.510935