Yes, there are 2 standard deviation indicators attached to the chart. The formula is the same as yours:
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StdDev (i) = SQRT (AMOUNT (j = i - N, i) / N)
AMOUNT (j = i - N, i) = SUM ((ApPRICE (j) - MA (ApPRICE (i), N, i)) ^ 2)
etc.
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Each SD indicator has its own N (Smoothing period), which in my attached chart was a fast one (10) and a slower one (20). I'd like to have both plotted on the same chart (with options I can choose for colors and also styles like histograms), with an alert when the faster one (N=10 in my example) crosses the slower one (N=20 in my example). The overall purpose is to give an alert when volatility increases.