condition mean min max ZT0-3 20.44303 20.44303 20.44303 ZT4-7 20.8902815 20.8902815 20.8902815 ZT8-11 21.0714575 21.0714575 21.0714575 ZT12-15 19.138635 19.138635 19.138635 ZT16-19 21.291159 21.291159 21.291159 ZT20-23 21.161835500000002 21.161835500000002 21.161835500000002