.. note:: :class: sphx-glr-download-link-note Click :ref:here  to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_gallery_specialty_plots_anscombe.py: ================== Anscombe's quartet ================== Anscombe's quartet_ is a group of datasets (x, y) that have the same mean, standard deviation, and regression line, but which are qualitatively different. It is often used to illustrate the importance of looking at a set of data graphically and not only relying on basic statistic properties. .. _Anscombe's quartet: https://en.wikipedia.org/wiki/Anscombe%27s_quartet .. image:: /gallery/specialty_plots/images/sphx_glr_anscombe_001.png :class: sphx-glr-single-img .. code-block:: default import matplotlib.pyplot as plt import numpy as np x = [10, 8, 13, 9, 11, 14, 6, 4, 12, 7, 5] y1 = [8.04, 6.95, 7.58, 8.81, 8.33, 9.96, 7.24, 4.26, 10.84, 4.82, 5.68] y2 = [9.14, 8.14, 8.74, 8.77, 9.26, 8.10, 6.13, 3.10, 9.13, 7.26, 4.74] y3 = [7.46, 6.77, 12.74, 7.11, 7.81, 8.84, 6.08, 5.39, 8.15, 6.42, 5.73] x4 = [8, 8, 8, 8, 8, 8, 8, 19, 8, 8, 8] y4 = [6.58, 5.76, 7.71, 8.84, 8.47, 7.04, 5.25, 12.50, 5.56, 7.91, 6.89] datasets = { 'I': (x, y1), 'II': (x, y2), 'III': (x, y3), 'IV': (x4, y4) } fig, axs = plt.subplots(2, 2, sharex=True, sharey=True, figsize=(6, 6), gridspec_kw={'wspace': 0.08, 'hspace': 0.08}) axs[0, 0].set(xlim=(0, 20), ylim=(2, 14)) axs[0, 0].set(xticks=(0, 10, 20), yticks=(4, 8, 12)) for ax, (label, (x, y)) in zip(axs.flat, datasets.items()): ax.text(0.1, 0.9, label, fontsize=20, transform=ax.transAxes, va='top') ax.tick_params(direction='in', top=True, right=True) ax.plot(x, y, 'o') # linear regression p1, p0 = np.polyfit(x, y, deg=1) x_lin = np.array([np.min(x), np.max(x)]) y_lin = p1 * x_lin + p0 ax.plot(x_lin, y_lin, 'r-', lw=2) # add text box for the statistics stats = (f'$\\mu$ = {np.mean(y):.2f}\n' f'$\\sigma$ = {np.std(y):.2f}\n' f'$r$ = {np.corrcoef(x, y)[0][1]:.2f}') bbox = dict(boxstyle='round', fc='blanchedalmond', ec='orange', alpha=0.5) ax.text(0.95, 0.07, stats, fontsize=9, bbox=bbox, transform=ax.transAxes, horizontalalignment='right') plt.show() .. _sphx_glr_download_gallery_specialty_plots_anscombe.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download :download:Download Python source code: anscombe.py  .. container:: sphx-glr-download :download:Download Jupyter notebook: anscombe.ipynb  .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot Gallery generated by Sphinx-Gallery _