condition mean min max ZT0-3 3.728965 2.9025350000000003 4.555395 ZT4-7 8.943345 8.943345 8.943345 ZT8-11 9.869599999999998 9.869599999999998 9.869599999999998 ZT12-15 0 0 0 ZT16-19 8.460094999999999 8.460094999999999 8.460094999999999 ZT20-23 6.9185099999999995 6.9185099999999995 6.9185099999999995