Selecting features by quartiles in QGIS

Question

I have a polygon layer. I drew a boxplot calculated from field area in the layer.

How can I select the features whose area value is within interquartile range (25%-75%)?

Answer 1

There are two expression functions (q1 and q3) which return %25 and %75 quartiles. You can use both in Select Features by Expression tool.

Docs:
q1: Returns the calculated first quartile from a field or expression.
q3: Returns the calculated third quartile from a field or expression.

$area > q1( $area ) and $area < q3( $area )

Different combinations can also be used.