Biostatistics 104: correlational analysis.

If both height and weight are normally distributed, we use the Pearson’s correlation; otherwise Spearman’s correlation coefficient will be presented. Spearman’s correlation is also applicable for two categorical ordinal variables like pain intensity (no, mild, moderate, severe) with burn-surface-area (< 10%, 10% 19%, 20% 29%, ≥ 30%). Table I shows the correlation coefficient between height and weight (both variables are normally distributed): Pearson’s r = 0.807 (p<0.001).