First of all, I'm not a statistics person but came across this site and figured I'd ask a potentially dumb question:
I'm looking at some P&L data where the line items are things such as Sales, Direct Cost, Advertising Cost, etc. I have 12 months of data and am trying to plot each of the line items on a scatter plot where x-axis is variability across the 12 months and the y-axis is the magnitude of the entire year (e.g. sum of 12 months).
I'm using std. dev for variability and what I end up getting is pretty much a line (bottom left to upper right) since the std dev is a factor of magnitude (if I'm saying that right). Is there a way to "normalize" std. dev. or calculate variability that isn't dependent on size/magnitude?