condition mean min max ZT0-3 3.178815 2.05796 4.08418 ZT4-7 1.622985 1.622985 1.622985 ZT8-11 2.42598 2.42598 2.42598 ZT12-15 9.427162500000001 8.838090000000001 10.016235 ZT16-19 6.76246 6.76246 6.76246 ZT20-23 5.530945 5.530945 5.530945