condition mean min max ZT0-3 234.760361 234.760361 234.760361 ZT4-7 206.4241695 206.4241695 206.4241695 ZT8-11 135.15068200000002 135.15068200000002 135.15068200000002 ZT12-15 209.265667 209.265667 209.265667 ZT16-19 115.84091500000001 115.84091500000001 115.84091500000001 ZT20-23 98.3690505 98.3690505 98.3690505