When Marjorie Yang took the stage in a grand, wood-paneled room at Hong Kong University, she was in high spirits. The 65-year-old business executive joked about being a nerd (she graduated from M.I.T. with a math degree), told stories about smoking cigarettes out of dormitory windows at boarding school, and explained to the assembled students that she had volunteered to speak first at the event because, as a rare woman among the ranks of Hong Kong tycoons, she was always fighting to make her voi