condition mean min max ZT0-3 12.206716666666667 8.18561 16.844099999999997 ZT4-7 25.5931 25.5931 25.5931 ZT8-11 23.7133 23.7133 23.7133 ZT12-15 21.7089375 20.844 22.573875 ZT16-19 27.667550000000002 27.667550000000002 27.667550000000002 ZT20-23 19.27635 19.27635 19.27635