diff --git a/module2/exo1/cosxsx.png b/module2/exo1/cosxsx.png
index 90c19d9683fc5673b35b3481174a8afb47b04e6f..cddaddf5bc376e73d8f3698c2b32903e6c3e4d3d 100644
Binary files a/module2/exo1/cosxsx.png and b/module2/exo1/cosxsx.png differ
diff --git a/module2/exo2/exercice_python_en.org b/module2/exo2/exercice_python_en.org
index 3fa3ccf29336c58bd51199063b7e9ded6861388e..3c0bef450e04beddf0fa90c6e9f0d2e0b5899dbe 100644
--- a/module2/exo2/exercice_python_en.org
+++ b/module2/exo2/exercice_python_en.org
@@ -92,3 +92,61 @@ followed by ~Tab~.
Now it's your turn! You can delete all this information and replace it
by your computational document.
+
+* Exercise 02-2
+
+Load the data:
+
+#+begin_src python :results value :session :exports both
+import numpy as np
+x = np.array([
+ 14.0, 7.6, 11.2, 12.8, 12.5, 9.9, 14.9, 9.4, 16.9, 10.2, 14.9, 18.1, 7.3, 9.8, 10.9,12.2, 9.9, 2.9, 2.8, 15.4, 15.7, 9.7, 13.1, 13.2, 12.3, 11.7, 16.0, 12.4, 17.9, 12.2, 16.2, 18.7, 8.9, 11.9, 12.1, 14.6, 12.1, 4.7, 3.9, 16.9, 16.8, 11.3, 14.4, 15.7, 14.0, 13.6, 18.0, 13.6, 19.9, 13.7, 17.0, 20.5, 9.9, 12.5, 13.2, 16.1, 13.5, 6.3, 6.4, 17.6, 19.1, 12.8, 15.5, 16.3, 15.2, 14.6, 19.1, 14.4, 21.4, 15.1, 19.6, 21.7, 11.3, 15.0, 14.3, 16.8, 14.0, 6.8, 8.2, 19.9, 20.4, 14.6, 16.4, 18.7, 16.8, 15.8, 20.4, 15.8, 22.4, 16.2, 20.3, 23.4, 12.1, 15.5, 15.4, 18.4, 15.7, 10.2, 8.9, 21.0
+])
+#+end_src
+
+#+RESULTS:
+
+Calculate the mean:
+
+#+begin_src python :results value :session :exports both
+np.mean(x)
+#+end_src
+
+#+RESULTS:
+: 14.113000000000001
+
+Calculate the minimum:
+
+#+begin_src python :results value :session :exports both
+np.min(x)
+#+end_src
+
+#+RESULTS:
+: 2.8
+
+Calculate the maximum:
+
+#+begin_src python :results value :session :exports both
+np.max(x)
+#+end_src
+
+#+RESULTS:
+: 23.4
+
+Calclurate the median:
+
+#+begin_src python :results value :session :exports both
+np.median(x)
+#+end_src
+
+#+RESULTS:
+: 14.5
+
+Calculate the standard deviation:
+
+#+begin_src python :results value :session :exports both
+np.std(x, ddof=1)
+#+end_src
+
+#+RESULTS:
+: 4.334094455301447
diff --git a/module2/exo3/exercice_python_en.org b/module2/exo3/exercice_python_en.org
index 5782f493934678ba782fb65634a4d86e5f3adefc..62975943bdd0b578ff6c8363ed6343825cfd8cdc 100644
--- a/module2/exo3/exercice_python_en.org
+++ b/module2/exo3/exercice_python_en.org
@@ -11,84 +11,52 @@
#+HTML_HEAD:
#+HTML_HEAD:
-* Some explanations
+* Exercise 02-3
-This is an org-mode document with code examples in R. Once opened in
-Emacs, this document can easily be exported to HTML, PDF, and Office
-formats. For more information on org-mode, see
-https://orgmode.org/guide/.
+Load the data:
-When you type the shortcut =C-c C-e h o=, this document will be
-exported as HTML. All the code in it will be re-executed, and the
-results will be retrieved and included into the exported document. If
-you do not want to re-execute all code each time, you can delete the #
-and the space before ~#+PROPERTY:~ in the header of this document.
-
-Like we showed in the video, Python code is included as follows (and
-is exxecuted by typing ~C-c C-c~):
-
-#+begin_src python :results output :exports both
-print("Hello world!")
+#+begin_src python :session :exports both
+import numpy as np
+x = np.array([
+ 14.0, 7.6, 11.2, 12.8, 12.5, 9.9, 14.9, 9.4, 16.9, 10.2, 14.9, 18.1, 7.3, 9.8, 10.9,12.2, 9.9, 2.9, 2.8, 15.4, 15.7, 9.7, 13.1, 13.2, 12.3, 11.7, 16.0, 12.4, 17.9, 12.2, 16.2, 18.7, 8.9, 11.9, 12.1, 14.6, 12.1, 4.7, 3.9, 16.9, 16.8, 11.3, 14.4, 15.7, 14.0, 13.6, 18.0, 13.6, 19.9, 13.7, 17.0, 20.5, 9.9, 12.5, 13.2, 16.1, 13.5, 6.3, 6.4, 17.6, 19.1, 12.8, 15.5, 16.3, 15.2, 14.6, 19.1, 14.4, 21.4, 15.1, 19.6, 21.7, 11.3, 15.0, 14.3, 16.8, 14.0, 6.8, 8.2, 19.9, 20.4, 14.6, 16.4, 18.7, 16.8, 15.8, 20.4, 15.8, 22.4, 16.2, 20.3, 23.4, 12.1, 15.5, 15.4, 18.4, 15.7, 10.2, 8.9, 21.0
+])
#+end_src
#+RESULTS:
-: Hello world!
-
-And now the same but in an Python session. With a session, Python's
-state, i.e. the values of all the variables, remains persistent from
-one code block to the next. The code is still executed using ~C-c
-C-c~.
-#+begin_src python :results output :session :exports both
-import numpy
-x=numpy.linspace(-15,15)
-print(x)
-#+end_src
-
-#+RESULTS:
-#+begin_example
-[-15. -14.3877551 -13.7755102 -13.16326531 -12.55102041
- -11.93877551 -11.32653061 -10.71428571 -10.10204082 -9.48979592
- -8.87755102 -8.26530612 -7.65306122 -7.04081633 -6.42857143
- -5.81632653 -5.20408163 -4.59183673 -3.97959184 -3.36734694
- -2.75510204 -2.14285714 -1.53061224 -0.91836735 -0.30612245
- 0.30612245 0.91836735 1.53061224 2.14285714 2.75510204
- 3.36734694 3.97959184 4.59183673 5.20408163 5.81632653
- 6.42857143 7.04081633 7.65306122 8.26530612 8.87755102
- 9.48979592 10.10204082 10.71428571 11.32653061 11.93877551
- 12.55102041 13.16326531 13.7755102 14.3877551 15. ]
-#+end_example
+** Sequence plot:
-Finally, an example for graphical output:
-#+begin_src python :results output file :session :var matplot_lib_filename="./cosxsx.png" :exports results
+#+begin_src python :session :results output file :var matplot_lib_filename="./sequence_plot.png" :exports both
import matplotlib.pyplot as plt
-plt.figure(figsize=(10,5))
-plt.plot(x,numpy.cos(x)/x)
+plt.figure(figsize=(6,4.5))
+plt.plot(x)
plt.tight_layout()
+plt.grid(color="lightgrey", linestyle="--")
+plt.xlim([0,100])
+plt.ylim([0,25])
plt.savefig(matplot_lib_filename)
print(matplot_lib_filename)
#+end_src
#+RESULTS:
-[[file:./cosxsx.png]]
+[[file:./sequence_plot.png]]
-Note the parameter ~:exports results~, which indicates that the code
-will not appear in the exported document. We recommend that in the
-context of this MOOC, you always leave this parameter setting as
-~:exports both~, because we want your analyses to be perfectly
-transparent and reproducible.
+** Histogram Plot
-Watch out: the figure generated by the code block is /not/ stored in
-the org document. It's a plain file, here named ~cosxsx.png~. You have
-to commit it explicitly if you want your analysis to be legible and
-understandable on GitLab.
+#+begin_src python :session :results output file :var matplot_lib_filename="./histogram.png" :exports both
+plt.figure(figsize=(6,4.5))
+plt.hist(x, edgecolor="black", alpha=.75, zorder=2)
+plt.grid(color="lightgrey", linestyle="--")
+plt.xlim([0,25])
+plt.ylim([0,25])
+plt.tight_layout()
+
+plt.savefig(matplot_lib_filename)
+print(matplot_lib_filename)
+#+end_src
-Finally, don't forget that we provide in the resource section of this
-MOOC a configuration with a few keyboard shortcuts that allow you to
-quickly create code blocks in Python by typing ~