Correlation coefficients:– Pearson’s Correlation coefficient: – Spearman’s Rank Correlation coefficientCoefficient of determination:– Is the percentage of variation in a variable that is explained by one or more of the others – Is generally obtained in a regression setup – Coefficient of determination = (Correlation coefficient)2 = r2 In the given question, a cardiologist found a highly significant correlation coefficient (r = 0.90, p= 0.01) between the systolic blood pressure values and serum cholesterol values of the patients attending his clinic, Since r = + 0.90 (p = 0.01; implies significant relationship), it means there is a strong positive correlation between systolic blood pressure (SBP) and serum cholesterol (SC); therefore as SBP increases, SC will also increase and vice-versa. Thus, a patient with a high level of systolic BP is also likely to have a high level of serum cholesterol AND a patient with a low level of systolic BP is also likely to have a low level of serum cholesterol. Since r = + 0.9; Coefficient of determination = r2 = (0.9)2 = 0.81 Interpretation of r2: 0.81 or 81% of variation in systolic blood pressure among patients can be explained by their serum cholesterol values and vice-versa.