condition mean min max ZT0-3 2.673575 2.673575 2.673575 ZT4-7 3.5821199999999997 3.5821199999999997 3.5821199999999997 ZT8-11 1.7584404999999999 1.7584404999999999 1.7584404999999999 ZT12-15 1.5717050000000001 1.5717050000000001 1.5717050000000001 ZT16-19 1.27448 1.27448 1.27448 ZT20-23 2.8317699999999997 2.8317699999999997 2.8317699999999997