QtiPlot - Data Analysis and Scientific Plotting

With just one-click you get access to an extensive list of data analysis routines: statistics analysis, sorting, FFT, data smoothing (Savitzky-Golay, Lowess, FFT smoothing, and moving window average), data filtering (low/high/band pass and band block filters), convolution/deconvolution, correlation, interpolation, numerical, integration/differentiation:

Built-in analysis routines.