How to 'cap' off the bottom of half of a Sphere?

Hello guys, I’m totally new to Blender. In fact, I just starting working with the program a few days ago. I’m working on a relatively simple model. Basically, what I want to know is how I can cap off the bottom of a sphere with a face. A picture will explain it better than words.

Select all the bottom edges by selecting them individually or box select them with B or circle select them with C or select edghe loop with Alt+LMB on the edge then press F

Ah, thanks! That did the trick.