The American Psychological Association (APA) has specific requirements about how statistical results are reported. These typically include the test used, degrees of freedom, test statistic value, p-value, and effect size. In this blog, I will walk you through recognizing components of an APA-style statistical report so that you will feel more confident reading, interpreting, and writing statistical reports.
Here is an example of a statistical result using an F-test:
F(2,34) = 2.51, p = .003, η2 = .04
The first part indicates the test used—in this case, the F-test. Other common tests include the chi-square (2) and t-test. Italicize English letters for statistical values (e.g., t, F, p), but leave Greek letters (e.g., χ) in regular font. The degrees of freedom associated with the test should be in parentheses following the statistical letter or symbol. Then, report the actual value of the test statistic to two decimal places after the equals sign.Make sure that you have a space on either side of the equals sign.
After a comma, report the p-value in italics, following the “.000” form with no leading zeroes and three decimal places. They often report eta squared (η²) as the effect size for an ANOVA F-test. Measures of effect sizes such as R2 and d are common for regressions and t-tests respectively. List the effect size after the p-value; if unrecognized, it may be unfamiliar.
Here is an example of what results might look like for a t-test:
t(6)= 0.54, p = .547, d = .05
And here is an example for a chi-square test:
2(18) = 4.25, p = .458
You should not list these results alone but always explain them. For example, you could write, “Variables X and Z strongly negatively correlate, r = -.60.” “The two groups were significantly different, t(4) = -4.21, p = .041.” Participants in the Group A scored significantly higher (M = 1.23, SD = 0.81) than Group B (M = 0.52, SD = 0.10).”