condition mean min max ZT0-3 2.909191666666667 2.219455 3.6793250000000004 ZT4-7 2.84191 2.84191 2.84191 ZT8-11 2.492615 2.492615 2.492615 ZT12-15 3.8879199999999994 3.738705 4.037134999999999 ZT16-19 3.907395 3.907395 3.907395 ZT20-23 2.1803 2.1803 2.1803