condition mean min max ZT0-3 16.198775 16.1869 16.21065 ZT4-7 17.6417 17.6417 17.6417 ZT8-11 27.16265 27.16265 27.16265 ZT12-15 0 0 0 ZT16-19 30.5469 30.5469 30.5469 ZT20-23 28.21395 28.21395 28.21395