condition mean min max ZT0-3 1.4282315 0.7643545 2.097405 ZT4-7 0.1394805 0.1394805 0.1394805 ZT8-11 0.880593 0.880593 0.880593 ZT12-15 1.12821775 1.0589285 1.1975069999999999 ZT16-19 2.3715200000000003 2.3715200000000003 2.3715200000000003 ZT20-23 0.954583 0.954583 0.954583