condition mean min max ZT0-3 19.3659637075 18.72861693 20.003310485 ZT4-7 18.49550009 18.15736801 18.83363217 ZT8-11 23.374228504999998 21.83358492 24.91487209 ZT12-15 17.23244131166667 16.417342213333335 18.04754041 ZT16-19 20.168672493333332 18.961557693333333 21.375787293333335 ZT20-23 17.73678967 16.59286252 18.88071682