condition mean min max ZT0-3 8.2397432995 6.494738378 9.984748221 ZT4-7 4.257202606 4.127125539 4.387279673 ZT8-11 4.3324819875 3.7398645024999997 4.9250994724999995 ZT12-15 2.59034778325 1.7342667760000001 3.4464287904999997 ZT16-19 1.5416842625 1.5230240734999998 1.5603444515 ZT20-23 2.73738378825 2.4521104355 3.0226571410000003