Above poster makes good points. If you can publish then that's awesome and never looks bad! If you can get a few credits for doing research then that is good too it also shows proof of your research, I never published but had 3 credits of research so I thought something was better than nothing. Research wasn't the center of my application but it's good to have and it depends on the type of application/applicant you are building. I had friends who did a lot of research and got multiple publications and were accepted, then I have other friends who never did research but still got in (granted it was a ~low tier school and I'm not saying to not do it). The hours depends totally on you but if it's like just 100 hours then that's not really much. Find research your interested in and do your best, if you don't publish it's not the end of the world, but if you manage to do it then it's great!