condition mean min max ZT0-3 11.721957 11.721957 11.721957 ZT4-7 11.736464000000002 11.736464000000002 11.736464000000002 ZT8-11 10.9543355 10.9543355 10.9543355 ZT12-15 9.8364955 9.8364955 9.8364955 ZT16-19 10.584657 10.584657 10.584657 ZT20-23 10.210011 10.210011 10.210011