Why is matplotlib's notched boxplot folding back on itself?

Question

I tried to make a notched boxplot using matplotlib, but found the notched box tends to overextend and then fold back on itself. This does not happen when I make a regular boxplo

Answer 1

It means that the distribution of the data is skewed. If two boxes' notches do not overlap, there is 95% confidence their medians differ.

The Notch displays the confidence interval around the median which is normally based on :

Maybe, you can alter the bootstrap parameter of the boxplot to tighten up the median's confidence interval.