
A query to the selected PitchTier object.
the standard deviation in the curve within a specified time window.
The curve consists of a sequence of line segments. The contribution of the line segment from (t_{1}, f_{1}) to (t_{2}, f_{2}) to the variancemultipliedbytime is
[ 1/4 (f_{1} + f_{2})^{2} + 1/12 (f_{1} – f_{2})^{2} ] (t_{2} – t_{1}) 
The standard deviation is the square root of: the sum of these values divided by toTime – fromTime.
To get the standard deviation in the points only, i.e. not weighted by the durations of the line pieces, Use PitchTier: Get standard deviation (points)... instead.
© ppgb, August 21, 2001