condition mean min max ZT0-3 21.933647 21.933647 21.933647 ZT4-7 18.776391 18.776391 18.776391 ZT8-11 15.231090000000002 15.231090000000002 15.231090000000002 ZT12-15 17.8050535 17.8050535 17.8050535 ZT16-19 17.0023555 17.0023555 17.0023555 ZT20-23 33.9629725 33.9629725 33.9629725