If we listen closely we hear that she researched which would entail asking questions of the people who work there. If one or more of the women she spoke with came from, what she perceived as, a nursing background then she is guilty of generalizing by stating 'a lot of girls' come from a nursing background. Most likely she was was drawing on whatever came to mind in order to make conversation. In one nights research at one brothel she has made the assumption that lots of girls who prostitute, come from nursing backgrounds? Yikes, Helen, not cool!