If the value of co-efficient of determination is 0.64, what is the value of coefficient of correlation ?

The Coefficient of Determination (R² or r²) is the square of Karl Pearson's Coefficient of Correlation (r), measuring the proportion of total variance in the dependent variable explained by the independent variable. Given r² = 0.64, taking the positive square root yields the coefficient of correlation r = √0.64 = 0.80.