condition mean min max ZT0-3 2.67851 2.67851 2.67851 ZT4-7 1.847615 1.847615 1.847615 ZT8-11 1.690465 1.690465 1.690465 ZT12-15 3.157625 3.157625 3.157625 ZT16-19 3.4769699999999997 3.4769699999999997 3.4769699999999997 ZT20-23 3.387445 3.387445 3.387445