With help from numpy one can calculate for example a linear fitting.
# plot the data itselfpylab.plot(x,y,'o')# calc the trendlinez = numpy.polyfit(x, y, 1)p = numpy.poly1d(z)pylab.plot(x,p(x),"r--")# the line equation:print"y=%.6fx+(%.6f)"%(z[0],z[1])