Statistics.java

/*
 * Copyright (c) 2016 by Gerrit Grunwald
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package eu.hansolo.medusa.tools;

import java.util.Collections;
import java.util.List;


/**
 * Created by hansolo on 06.12.16.
 */
public class Statistics {


    // ******************** Methods *******************************************
    public static double getMean(final List<Double> DATA) { return DATA.stream().mapToDouble(v -> v).sum() / DATA.size(); }

    public static double getVariance(final List<Double> DATA) {
        double mean = getMean(DATA);
        double temp = 0;
        for (double a : DATA) { temp += ((a - mean) * (a - mean)); }
        return temp / DATA.size();
    }

    public static double getStdDev(final List<Double> DATA) { return Math.sqrt(getVariance(DATA)); }

    public static double getMedian(final List<Double> DATA) {
        int size = DATA.size();
        Collections.sort(DATA);
        return size % 2 == 0 ? (DATA.get((size / 2) - 1) + DATA.get(size / 2)) / 2.0 : DATA.get(size / 2);
    }

    public static double getMin(final List<Double> DATA) { return DATA.stream().mapToDouble(v -> v).min().orElse(0); }

    public static double getMax(final List<Double> DATA) { return DATA.stream().mapToDouble(v -> v).max().orElse(0); }
}