LinearRegressionCalculator.java

import org.apache.commons.math3.stat.regression.SimpleRegression;
import java.util.List;

public class LinearRegressionCalculator {
    /**
     * Calculates the slope and intercept of the line of best fit using simple linear regression.
     *
     * @param data A List<Double> object that represents the 'y' values of the data points.
     * @return A double array of size 2 where the first element is the slope and the second element is the intercept.
     */
    public double[] calculateLinearRegression(List<Double> data) {
        SimpleRegression regression = new SimpleRegression();

        // Add data to the regression model
        for (int i = 0; i < data.size(); i++) {
            regression.addData((double) i, data.get(i));
        }

        double[] result = new double[2];
        result[0] = regression.getSlope();     // slope
        result[1] = regression.getIntercept(); // intercept

        return result;
    }
}