Update index.md

Author: AndrzejRomaniuk

index.md

@@ -188,7 +188,7 @@ Modify the block below if there are any special requirements.
     Participants must have access to a computer with a
     Mac, Linux, or Windows operating system (not a tablet, Chromebook, etc.) that they have administrative privileges on.
   {% endif %}
-  They should have a few specific software packages installed (listed <a href="#setup">below</a>).
+  They should have a few specific software installed (listed <a href="#setup">below</a>). Additonally, please download <a href = "https://swcarpentry.github.io/python-novice-gapminder/files/python-novice-gapminder-data.zip"> the gapminder dataset </a>.
 </p>
 
 {% comment %}