Matplotlib: plot indicating the precision of measurements
One can use the matplotlib.axes.Axes.errorbar class.

From this example in the documentation:

# example error bar values that vary with x-position
error = 0.1 + 0.2 * x

fig, (ax0, ax1) = plt.subplots(nrows=2, sharex=True)
ax0.errorbar(x, y, yerr=error, fmt='-o')
ax0.set_title('variable, symmetric error')


Acknowledgments: Thanks to Emre!