Why does my rendered movie clip have no audio? I am a Blender newbie, and know that I will have to supply additional info...Please be patient with me :-)

I followed this video by Oliver Villar, https://www.youtube.com/watch?v=nU8zqn091rM. I am using a 54 second video shot with a phone. The rendered AVI video has no audio.

I used a single tracker, placed on the cross on the green parament, to do the 2D stabilization.
The original video is here: https://vimeo.com/229907878 
The stabilized video is here: https://vimeo.com/229907728 
Here is a screenshot of how my compositor is set up:





Let me know of anything else I can provide. And, thanks so much for the help!
Have you selected a audio codec before rendering ? 
By default it's on "none"
(Properties panel -> render -> encoding)