Why, in general, is the variance of volume changes higher than variance of price changes?
I understand that these two quantities are functions of some very different factors, but I don't understand fully why the variance of volume is changing so much.
I've heard that even if one accounts for seasonal changes in volatility (by standardizing daily stock volume by daily volume of basket of stocks/volume of index), the variance of the volume changes is much higher.
Edition : I meant quantities measured in percentage. High jumps in volume are very common, whereas high price changes aren't.