e-Articles (Chapter 9)
Here are some full-length research articles in which statistical tests were conducted on correlation coefficients. To view any article, simply click on its title. (NOTE: No claim is made that these articles are perfect in all respects. By carefully reviewing them, you will hone your skills at being able both to decipher and to critique statistically-based research reports.)
In this research report, Tables 2 and 3 each contain several Pearson correlations. Each of these correlations was tested to see if it was significantly different from 0. Can you tell whether these tests were conducted in a 1-tailed or 2-tailed fashion? In Table 3, can you locate the r that shows up as being nonsignificant when it should have had an asterisk attached to it?
Illustrates how Spearman rank-order correlations can be tested to determine if they are significantly different from 0. See the last paragraph of the "Data Analysis" portion of the article's "Method" section, the 2nd paragraph of "Results," and Table 2.
Shows how the hypothesis testing procedure can be used to see if a correlation coefficient is significantly different from zero. Such a test was performed 136 times, with results presented in Tables 3, 4, and 5.
In this study, the researchers conducted tests on 6 values of Pearson's product-moment correlation, with each of these tests being two-tailed in nature. The presentation of the rs and the ps shows nicely that the p in such a test gets smaller as the value of r moves away from 0. See the final paragraph of the portion of "Results" dealing with "Salivary Corisol Concentrations." (NOTE: a comparison of the of the ps across the 2 sets of rs requires sample sizes that are equal or nearly equal, as is the case here with nFO = nFO = 22.)
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Schuyler W. Huck