Issue on page /01-Introduction-To-Causality.html

[Henry Liu]

I found there may be a typo for the expression of Average Treatment Effect
"""Finally, we reorder the terms, merge some expectations, and lo and behold:

(The Expression here seems to be wrong)

This simple piece of math encompasses all the problems we will encounter in causal questions. """

[Matheus Facure]

I'm assuming you means this expression?

I could't find the mistake. Can you be more specific? Feel free to reopen the issue afterwards.