I am a newbie around here, so forgive me for the basic question.
Here on this post I mentioned, you say we should consider trimming when median Q drops below 20. But which one is the median Q on the parametric seven-number summary table? Is it the 25th or the 50th percentile (or neither)?
Also, I often see the terms "trim" and "truncate". What are the differences between them?
Great question! The median quality score corresponds to the 50th percentile in the parametric seven-number summary table. It should be annotated as the median as well, for reference - here is a screenshot from an example interactive quality plot and summary table that demonstrates this: