condition mean min max ZT0-3 19.308869835 12.79661392 25.82112575 ZT4-7 10.69116848 9.774986855000002 11.607350104999998 ZT8-11 8.69405251725 8.437894116999999 8.9502109175 ZT12-15 7.028982715750001 6.7590637525 7.298901679 ZT16-19 12.672707299999999 10.83687397 14.50854063 ZT20-23 18.5033133075 17.535432265 19.471194349999998