condition mean min max ZT0-3 14.144328 14.144328 14.144328 ZT4-7 12.4480465 12.4480465 12.4480465 ZT8-11 12.5844645 12.5844645 12.5844645 ZT12-15 12.600896 12.600896 12.600896 ZT16-19 13.50025 13.50025 13.50025 ZT20-23 13.9631085 13.9631085 13.9631085