condition mean min max ZT0-3 17.029778 17.029778 17.029778 ZT4-7 18.653488 18.653488 18.653488 ZT8-11 15.8527465 15.8527465 15.8527465 ZT12-15 13.351825 13.351825 13.351825 ZT16-19 15.727394499999999 15.727394499999999 15.727394499999999 ZT20-23 16.330197 16.330197 16.330197