condition mean min max ZT0-3 0.613654508 0.607399163 0.619909853 ZT4-7 1.2932383341666664 0.922415338 1.6640613303333331 ZT8-11 2.5325817075 2.1562041373333334 2.9089592776666664 ZT12-15 1.9641975379999999 1.6772191959999998 2.25117588 ZT16-19 2.2668544518333333 1.896261276 2.6374476276666665 ZT20-23 2.034193247 1.7377860409999997 2.330600453