What correlation is obtained when the Pearson correlation is computed for data that have been converted to ranks?
A)the Spearman correlation
B)the point-biserial correlation
C)the phi coefficient
D)the simple correlation

Question

What correlation is obtained when the Pearson correlation is computed for data that have been converted to ranks?​
A)​the Spearman correlation
B)​the point-biserial correlation
C)​the phi coefficient
D)​the simple correlation

Quizplus · Accepted Answer

When data is converted to ranks, the appropriate correlation to use is the Spearman correlation coefficient. The Spearman correlation coefficient measures the strength and direction of the monotonic relationship between two variables, which is a non-parametric measure that operates on the rank-ordered values of the data. The Pearson correlation coefficient, on the other hand, assumes that the variables are normally distributed and measures the strength and direction of the linear relationship between the variables, which may not be appropriate for rank data. Therefore, the correlation obtained when the Pearson correlation is computed for data that have been converted to ranks is equivalent to the Spearman correlation coefficient.

What Correlation Is Obtained When the Pearson Correlation Is Computed