condition mean min max ZT0-3 21.326217 21.326217 21.326217 ZT4-7 20.388159 20.388159 20.388159 ZT8-11 20.412205999999998 20.412205999999998 20.412205999999998 ZT12-15 19.003731000000002 19.003731000000002 19.003731000000002 ZT16-19 22.107315 22.107315 22.107315 ZT20-23 24.816173499999998 24.816173499999998 24.816173499999998