condition mean min max ZT0-3 0.7324911666666667 0.5936015 0.899011 ZT4-7 0.865345 0.865345 0.865345 ZT8-11 2.1268700000000003 2.1268700000000003 2.1268700000000003 ZT12-15 2.3333025000000003 1.9374 2.7292050000000003 ZT16-19 1.28084 1.28084 1.28084 ZT20-23 2.14397 2.14397 2.14397