condition mean min max ZT0-3 3.665255 3.665255 3.665255 ZT4-7 3.177135 3.177135 3.177135 ZT8-11 3.2272100000000004 3.2272100000000004 3.2272100000000004 ZT12-15 3.3514299999999997 3.3514299999999997 3.3514299999999997 ZT16-19 5.46339 5.46339 5.46339 ZT20-23 5.048205 5.048205 5.048205