condition mean min max ZT0-3 19.28817 4.68281 27.7665 ZT4-7 6.52605 6.52605 6.52605 ZT8-11 8.8582 8.8582 8.8582 ZT12-15 11.7379125 8.504574999999999 14.97125 ZT16-19 21.281950000000002 21.281950000000002 21.281950000000002 ZT20-23 33.0453 33.0453 33.0453