condition mean min max ZT0-3 15.2450231575 15.00290337 15.487142945 ZT4-7 12.798298975 11.83639599 13.76020196 ZT8-11 20.3995737125 18.166407980000002 22.632739445 ZT12-15 25.253323334999997 23.71935187 26.787294799999998 ZT16-19 21.472009225 21.13824015 21.8057783 ZT20-23 26.0695791625 25.48711857 26.652039755