39 lines
1.3 KiB
Java
39 lines
1.3 KiB
Java
import static java.lang.Math.pow;
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import java.util.Arrays;
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import static java.util.Arrays.stream;
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import org.apache.commons.math3.special.Gamma;
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public class Test {
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static double x2Dist(double[] data) {
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double avg = stream(data).sum() / data.length;
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double sqs = stream(data).reduce(0, (a, b) -> a + pow((b - avg), 2));
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return sqs / avg;
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}
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static double x2Prob(double dof, double distance) {
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return Gamma.regularizedGammaQ(dof / 2, distance / 2);
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}
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static boolean x2IsUniform(double[] data, double significance) {
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return x2Prob(data.length - 1.0, x2Dist(data)) > significance;
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}
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public static void main(String[] a) {
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double[][] dataSets = {{199809, 200665, 199607, 200270, 199649},
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{522573, 244456, 139979, 71531, 21461}};
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System.out.printf(" %4s %12s %12s %8s %s%n",
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"dof", "distance", "probability", "Uniform?", "dataset");
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for (double[] ds : dataSets) {
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int dof = ds.length - 1;
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double dist = x2Dist(ds);
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double prob = x2Prob(dof, dist);
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System.out.printf("%4d %12.3f %12.8f %5s %6s%n",
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dof, dist, prob, x2IsUniform(ds, 0.05) ? "YES" : "NO",
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Arrays.toString(ds));
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}
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}
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}
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