condition mean min max ZT0-3 2.4093475 2.02775 2.790945 ZT4-7 0.911042 0.911042 0.911042 ZT8-11 2.2883 2.2883 2.2883 ZT12-15 0 0 0 ZT16-19 2.4072999999999998 2.4072999999999998 2.4072999999999998 ZT20-23 2.8688700000000003 2.8688700000000003 2.8688700000000003