What does the writing style apa mean?

According to the Purdue University Online Writing Lab (OWL),

"Begin a new page. Your abstract page should already include the page header (described above). On the first line of the abstract page, center and bold the Word "Abstract" (otherwise unformatted, italics, underlining, or quotation marks).

Beginning with the next line, write a concise summary of the key points of your research. (Do not indent.) Your abstract should contain at least your research topic, research questions, participants, methods, results, data analysis, and conclusions. You may also include possible implications of your research and future work you see connected with your findings. Your abstract should be a single paragraph double-spaced. Your abstract should be between 150 and 250 Words.

You may also want to list keyWords from your paper in your abstract. To do this, center the text and type KeyWords:(italicized) and then list your keyWords. Listing your keyWords will help researchers find your work in databases.".

See the related link, the Purdue University Online Writing Lab (OWL) for an actual abstract page.