How to add trendline in python matplotlib dot (scatter) graphs?

python scatter trendline
user3476791 picture user3476791 · Oct 19, 2014 · Viewed 113.2k times · Source

How could I add trendline to a dot graph drawn using matplotlib.scatter?

Answer

martinenzinger picture martinenzinger · Oct 19, 2014

as explained here

With help from numpy one can calculate for example a linear fitting.

# plot the data itself
pylab.plot(x,y,'o')

# calc the trendline
z = 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])

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