Collect paired data values for two variables
Calculate the mean of each variable
Subtract each mean from its corresponding data value to get deviations
Multiply each pair of deviations
Sum all the products of deviations
Square each deviation for both variables
Sum the squared deviations for each variable
Divide the sum of deviation products by the square root of the product of the two sums of squared deviations
Use the formula: r = Σ[(x – xÌ„)(y – ȳ)] / √[Σ(x – xÌ„)² × Σ(y – ȳ)²]
Interpret the result as a value between -1 and 1