I am not aware, if the data-set presented contains users from India also...
Let us analyse the user sets from India.
Majority users can be put into two sets of people, "
employed" and "
others" (this include students etc).
Let us take the first category, "
employed" and let us assume that people who shall be trying out new apps on Friday, are those, who have the weekends off.
Usually these sets of people would be working in multi-nationals, IT Services companies or Startups.
Since these sets of people are paid reasonably well, and they like to be in trend (like having the latest gadget, if they could afford it with cash/credit) and adding up the fact that mobile phones are replaced in between 18 to 24 months;it can be deduced that most of these people would have a device with a reasonable storage available to them.
Also, large number of people now, keep their default storage as the SD Card, including for apps.
Now, let us take the second set of users, "
others"; I believe, the concept of "
friday-app-unInstalls" may not be applicable to them.