Writers in the behavioral and social sciences often discuss large amounts of data. If it is very detailed or not directly relevant to the topic, writers place the material in appendices. Tables display numerical data in appendices. The "Publication Manual of the American Psychological Association, (6th edition)" provides guidelines for both appendices and tables.
Include any appendices at the very end of the paper. Identify appendices by sequential capital letters. If there is only one appendix, omit the identifying letter. Put each appendix on a separate page. Center "Appendix" without quotation marks and its corresponding letter on the top line, such as: Appendix A.
According to APA format, a table has at least three columns and rows. A horizontal line extends under the title, under the headings and at the bottom of the table. The table has no vertical lines. Use a consistent font style and size throughout. Number tables using sequential Arabic numerals. In the top left corner, put "Table" without quotation marks, the appendix letter, if there is one, and the table number, such as: Table A2. Use this identifier when referring to the table in text. On the second line, place a title that fully explains the table, for example: Test Scores of Experimental Group, Placebo Group and Control Group
Each column has a short heading. Headings do not extend beyond the width of the longest entry. Headings briefly describe the data underneath, such as: Group, Pretest, Mid-test and Post Test. The far left column has subheadings; for example, Group can be divided into Control, Experimental and Placebo. The far left column heading and its subheadings are left-justified; the others are centered. The subheadings are not separated by horizontal lines. The numerals in the table all have the same number of decimal places.