Can the network admin see my internet activity?

That depends on the networking setup...

But short answer is yes they can if they were really trying to do that...

If you are plugged into a hub, and not switch, broadcast traffic is available across all ports...

Using a simple utility like wireshark, you can see any data that is going thru the hub, and who it is coming from (the ip of the machine, host name, etc) wireshark can sniff packets basically...

But they would really have to know about networking to do that... and they would really want to get at you in order to sit there and sift thru all of that data coming thru...

Good luck...

EDIT : Any data sent over a secure connection cannot be sniffed, such as encrypted VPN connections, and SSL connections, the data will be scrambled to a point of 100% non legibility... that is the purpose of secure encrypted connections..

consequently they're the admin. yet you are able to constantly sparkling up what you probably did earlier you sign off. I worked at IBM and that they've been vast Brother, understanding each circulate you made because of the fact of being on a LAN. there is not any way they are in a position to bring up what sites you went to in case you sparkling all historic previous.

They can, its set up that way at my school and I've seen it at work for myself, though I don't know why the guy in charge of your apartment would want to view what your viewing unless he's extremely bored.

If they have it set up to do so, yes.