condition mean min max ZT0-3 1.6819000000000002 1.6819000000000002 1.6819000000000002 ZT4-7 1.290765 1.290765 1.290765 ZT8-11 0.9917594999999999 0.9917594999999999 0.9917594999999999 ZT12-15 1.22064 1.22064 1.22064 ZT16-19 1.2468650000000001 1.2468650000000001 1.2468650000000001 ZT20-23 1.335325 1.335325 1.335325