6502 Is = 1 - n(n2 - 1) In this formula, D represents the difference between ranks for each individual. Using this formula, you get Is = -0.30. These two estimates of the Spearman correlation are different for the following reason: O You do not use the Pearson correlation formula when calculating the Spearman correlation. O The formula that uses the differences (D) loses accuracy when there are many ties. O The formula that uses the differences (D) is always only a rough estimate of Is. O The Pearson correlation formula applied to the ranks loses accuracy when there are many ties