Example 2: Sign Test

This example tests the null hypothesis that at least 75 percent of a population is negative. Because , the null hypothesis at the 5-percent level of significance is rejected.

import java.text.*;
import com.imsl.stat.*;

public class SignTestEx2 {

    public static void main(String args[]) {
        double[] x = {
            92.0, 139.0, -6.0, 10.0, 81.0, -11.0, 45.0, -25.0, -4.0,
            22.0, 2.0, 41.0, 13.0, 8.0, 33.0, 45.0, -33.0, -45.0, -12.0
        };
        SignTest st = new SignTest(x);
        NumberFormat nf = NumberFormat.getInstance();
        nf.setMaximumFractionDigits(6);

        st.setPercentage(0.75);
        st.setPercentile(0.0);
        System.out.println("Probability = " + nf.format(st.compute()));
        System.out.println("Number of positive deviations = "
                + st.getNumPositiveDev());
        System.out.println("Number of ties = " + st.getNumZeroDev());
    }
}

Output

Probability = 0.922543
Number of positive deviations = 12
Number of ties = 0