1) This is the formula for my "downward volatility" , i dont know exactly the term for it, but if you calculate this, you will get that value, which will then show you the volatility of only the down movements, which should give you a risk understanding of bitcoin price crashes, because price increase doesnt matter, that is beneficial.
This is a formula for calculating standard deviation. But it makes no sense in the way you use it (that most likely explains the reason why you don't know a name for it), since when calculating an average for
x, you use
all values...
Your "only downward volatility" by implication includes "upward volatility" as well
No it doesnt. This is the formula which gives you the "relative downward volatility" to be more precise. Yes you need the upward values to calculate them mean, but that is neutral.
So you only look for the downward volatility, relative to the mean, that is a more precise definition.
It does make sense and it has pretty good statistical significance.