Ohio State University doctoral candidate Aryn Karpinski has conducted the kind of statistical study that guarantees headlines, 20-second mentions on network and local newscasts, and lots of comments on tech news Web sites and blogs. She knew she was writing about a media-friendly topic, but she still confesses to receiving a crash-course in sudden news exposure. The name of her study: “A Description of Facebook Use and Academic Performance Among Undergraduate and Graduate Students.”