The correlation coefficient of choice when both sets of measurements are in rank-order form and when fewer than 30 pairs of measurements are involved is
A) the Pearson r.
B) the tetrachoric r.
C) the Spearman rho.
D) the ROTC.

Question

Quizplus · Accepted Answer

The Spearman correlation coefficient is the best choice in this case, as it is designed to measure the relationship between two variables when they are in rank-order form. It is also robust to outliers and does not assume a linear relationship. The tetrachoric correlation coefficient is used when both variables are measured on a dichotomous scale, while the ROTC is not a standard statistical method. The Pearson correlation coefficient is appropriate for continuous variables, but may not be the best choice when dealing with rank-order variables or small sample sizes.

The Correlation Coefficient of Choice When Both Sets of Measurements