condition mean min max ZT0-3 17.092475 14.4298 19.75515 ZT4-7 13.51065 13.51065 13.51065 ZT8-11 17.4226 17.4226 17.4226 ZT12-15 0 0 0 ZT16-19 19.293 19.293 19.293 ZT20-23 16.526200000000003 16.526200000000003 16.526200000000003