Displaying LaTeX estimator notation with caret and subscript

[WWGD]

TL;DR

How to write Latex for $y_i$ with a caret , i.e., y^_i?

Hi,
Trying to Latex in an estimator y^ together with an index, y_i . The latter is obvious as $y_i$, but I can't get the estimator ^ without mangling it all.
Any ideas?

 

[Orodruin]

$\hat y_i$?

 

[WWGD]

$\hat y_i$?

Thank you.