condition mean min max ZT0-3 1.8068851714999998 0.686390155 2.927380188 ZT4-7 4.673003286 4.5565140809999995 4.789492491000001 ZT8-11 5.0853375530000005 4.9776516065 5.193023499500001 ZT12-15 8.667194831 7.6447795874999995 9.6896100745 ZT16-19 12.4837892275 12.061386785 12.90619167 ZT20-23 16.41204038 15.773001780000001 17.05107898