condition mean min max ZT0-3 17.5758046575 17.08921149 18.062397824999998 ZT4-7 8.1913215475 6.983748983 9.398894112 ZT8-11 13.062378198249998 9.461637266499999 16.66311913 ZT12-15 17.2015028275 17.10641785 17.296587805 ZT16-19 16.089968417500003 14.84586226 17.334074575000002 ZT20-23 21.5768206825 19.764598075 23.38904329