As far as I understand, IQR filters out data if it is not between the 25th and 75th percentile, but I do not understand what values from the dataset are being ranked and needs to be within this range?
IQR is a measure of variance of a variable (based on its 25th - 75th percentile from concentrations across all samples) - all variables are ranked based on their IQRs and those at the lower tail (i.e. 5% at the bottom) will be removed (near constant). Our data filtering page provides detailed explanation on this procedure. Below is a screenshot of the related text.
Arh yes of course. Thank you for your reply, it was helpful.