Answer: by presenting factual information.
The author of this passage wants to inform the readers of the most popular fields of studies for associate's degree recipients. In order to do so, he cites data that was compiled by the National Center for Education Statistics. This evidence is factual information, as it can be proven right or wrong, and is based on careful research. It provides strong support for the author's argument.
Answer is Tim O'Brien incorporates literary devices in The Things They Carried, such as imagery, point of view, setting, and symbolism to produce reactions from the reader.