condition mean min max ZT0-3 16.128886 16.128886 16.128886 ZT4-7 17.837688999999997 17.837688999999997 17.837688999999997 ZT8-11 16.9592555 16.9592555 16.9592555 ZT12-15 15.8306185 15.8306185 15.8306185 ZT16-19 15.383522500000002 15.383522500000002 15.383522500000002 ZT20-23 16.006611 16.006611 16.006611