task in Data Science, especially if we are performing an A/B Test to understand the effects of a given variable over those groups.

The problem is that the world is just… well, real. I mean, it is very beautiful to think of a controlled environment where we can isolate just one variable and measure the effect of it. But what happens most of the time is that life just runs over everything, and the next thing you know, your boss is asking you to compare the effect of the latest campaign on customers’ expenses.

But you never prepared the data for the experiment.…