condition mean min max ZT0-3 0.4668189166666667 0.0849255 1.1830205 ZT4-7 3.56637 3.56637 3.56637 ZT8-11 9.196415 9.196415 9.196415 ZT12-15 1.61993725 0.9638045 2.2760700000000003 ZT16-19 1.241345 1.241345 1.241345 ZT20-23 0.092117 0.092117 0.092117