condition mean min max ZT0-3 20.240295 15.35459 25.126 ZT4-7 19.53725 19.53725 19.53725 ZT8-11 62.0914 62.0914 62.0914 ZT12-15 0 0 0 ZT16-19 31.1839 31.1839 31.1839 ZT20-23 11.6024 11.6024 11.6024