In just feel it's not a good analysis because bitcoin it's calculated pegged to USD and Monero is calculated pegged to Bitcoin, I think it'll be impossible for any coin pegged to a currency to be less volatile than that currency.
I understand where you're coming from but the fact is you cannot exchange USD for Monero so a USD/XMR pairing doesn't mean much. Why shouldn't I also have to calculate bitcoin into euros, pounds, dinars, yen and everything else and then make a mass average for Monero?