condition mean min max ZT0-3 3.499136666666667 1.9753 4.471595000000001 ZT4-7 1.99709 1.99709 1.99709 ZT8-11 2.095595 2.095595 2.095595 ZT12-15 6.959385 5.847035 8.071735 ZT16-19 8.84154 8.84154 8.84154 ZT20-23 9.869250000000001 9.869250000000001 9.869250000000001