• In this lesson, we will learn how to measure the coefficient of correlation for two sets of ranking. • The coefficient of correlation, r, measures the strength of association or correlation between two sets of data that can be measured. Sometimes, the data is not measurable but can only be ordered, as in ranking. • For example, two students can be asked to rank toast, cereals, and dim sum in ...

The Kendall (1955) rank correlation coefficient evaluates the degree of similarity between two sets of ranks given to a same set of objects. This coefficient depends upon the number of inversions of pairs of objects which would be needed to transform one rank order into the other. In order to do so, each rank order is represented by the set of all pairs of objects (e.g., [a,b] and [b,a] are the...

Sir,—The hypothesis advanced by Narang and Linter [1] concerning the cause of unilateral extradural blockade is intriguing. However, I must take exception to their mathematics. Using the data from their table I, I have calculated the percentage of unsatisfactory blocks at each S—EDS (skin— extradural space distance) (table I). Spearmans rank correlation remains the same, but the authors' statem...