condition mean min max ZT0-3 1.9809811666666666 1.2773945 3.1215599999999997 ZT4-7 1.4824000000000002 1.4824000000000002 1.4824000000000002 ZT8-11 1.7962500000000001 1.7962500000000001 1.7962500000000001 ZT12-15 1.5125035 0.535092 2.489915 ZT16-19 1.214779 1.214779 1.214779 ZT20-23 2.4908 2.4908 2.4908