Quote Originally Posted by KBlaix
You are likely to have a faster connection when connected by a hard wire rather than wirelessly, but that won't affect your roommates connection at all. The only thing that will affect their connection is if you downloading a lot of large files, then while you are downloading those files their connection will be slower. If they are downloading large files though, you will have a slower connection.
KBlaix's answer makes more sense than mine
you (or your friend) are only slowing another person's connection down if you are downloading a lot of large files. If you are only using the internet for browsing or emailing you won't slow anyone's connection down whether you are using a wired or a wireless connection.