A researcher is interested in anxiety and how it might affect performance on scholastic aptitude tests. He has a clinical psychologist assess the anxiety of subjects by ranking them from 1 through 20....

A researcher is interested in anxiety and how it might affect performance on scholastic aptitude tests. He has a clinical psychologist assess the anxiety of subjects by ranking them from 1 through 20. Then he administers a standardized aptitude test to each of the 20 subjects and converts their IQ scores to ranks. Which correlation coefficient should the researcher calculate for the data? Explain your answer.