stdev
Standard Deviation
stdev(source, period)
Parameters
Standard Deviation - stdev(source, period)
Measures dispersion from mean. Higher values indicate greater volatility.
- source (field): Data series
- period (int): Number of periods
Formula
STDEV = sqrt(Σ(x - mean)² / N)
Uses population standard deviation
Examples
// volatility expanding (higher than 20 bars ago)
x = stdev(close, 20); x > x[20];
// low volatility environment
stdev(close, 14) < 2;
// volatility spike (current > 2x average)
stdev(close, 20) > sma(stdev(close, 20), 50) * 2;
Returns
Non-negative float (volatility measure)