Looking on the internet deeply has found these results:

for each X_i , i is the most popular phrase on the web.

for each x_i where 10 results on the web	for each X_i , i 11 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	distributions normal distribution convolution. asked Sep 10�... For each $X_i$ I have a weighting factor $w_i$. What is the ... probability theory statistics probability

for each x_i where

10 results on the web

for each X_i , i

11 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.