source: src/main/java/parties/in4010/q12015/group10/MeanAndVariance.java@ 126

package parties.in4010.q12015.group10;

public class MeanAndVariance {

        // Calculate the average error
        public static double getMeanError(double[] var1, double[] var2) {
                double meanError = 0;
                int arrayLength = var1.length;

                for (int arrayIndex = 0; arrayIndex < arrayLength; arrayIndex++) {
                        meanError = meanError + var1[arrayIndex] - var2[arrayIndex];
                }
                meanError = meanError / ((double) arrayLength);
                return meanError;
        }

        public static double getVarianceError(double[] var1, double[] var2) {
                // by definition: VAR = E[X^2] - (E[X])^2
                double meanError = 0;
                double meanSquaredError = 0;
                double varianceError = 0;
                int arrayLength = var1.length;

                for (int arrayIndex = 0; arrayIndex < arrayLength; arrayIndex++) {
                        meanError = meanError + var1[arrayIndex] - var2[arrayIndex];
                        meanSquaredError = meanSquaredError
                                        + (var1[arrayIndex] - var2[arrayIndex])
                                        * (var1[arrayIndex] - var2[arrayIndex]);
                }
                meanError = meanError / ((double) arrayLength);
                meanSquaredError = meanSquaredError / ((double) arrayLength);
                varianceError = meanSquaredError - meanError * meanError;
                return varianceError;
        }
}