condition mean min max ZT0-3 11.63917 10.55056 12.9204 ZT4-7 8.684615 8.684615 8.684615 ZT8-11 13.1964 13.1964 13.1964 ZT12-15 16.930775 15.4373 18.42425 ZT16-19 12.9489 12.9489 12.9489 ZT20-23 12.824190000000002 12.824190000000002 12.824190000000002