Prices are calculated daily. To calculate price for a given cryptocurrency, we select top 10 global exchanges by volume in USD, that are trading this cryptocurrency. If cryptocurrency was not traded for USD, we use trading data for BTC and convert the price using USD/BTC price for that date. From top 10 selected exchanges we take close price for each exchange and calculate mean which is then the Price that we display.
Volatility is a statistical measure of the dispersion of returns for a given cryptocurrency. It is calculated as a square root of variance of returns.