condition mean min max ZT0-3 22.646216666666668 18.5444 25.90605 ZT4-7 11.161750000000001 11.161750000000001 11.161750000000001 ZT8-11 15.16985 15.16985 15.16985 ZT12-15 27.055300000000003 24.826900000000002 29.2837 ZT16-19 22.993250000000003 22.993250000000003 22.993250000000003 ZT20-23 31.21245 31.21245 31.21245