condition mean min max ZT0-3 2.0628216666666668 1.95815 2.252615 ZT4-7 1.7479900000000002 1.7479900000000002 1.7479900000000002 ZT8-11 1.656275 1.656275 1.656275 ZT12-15 0.5648695 0.3519265 0.7778125 ZT16-19 1.027038 1.027038 1.027038 ZT20-23 0.9426295 0.9426295 0.9426295