Todennakoisyyslaskenta I viikko 4 tehtava 1 koodi

Tehtavat4.java

package viikko4;

// https://github.com/coderodde/DiscreteRandomVariables.java
import io.github.coderodde.prob.randomvariables.support.BinomialDistribution;
import io.github.coderodde.prob.randomvariables.support.PoissonDistribution;
import java.math.BigDecimal;
import java.math.RoundingMode;

public class Tehtavat4 {

    public static void tehtava1() {
        System.out.println("k: f(k)");
        System.out.println("Binomial:");
        
        BinomialDistribution binomial = 
                new BinomialDistribution(50L, 1.0 / 13.0);
        
        for (int k = 0; k <= 5; ++k) {
            System.out.print(k + ": ");
            
            System.out.println(
                    binomial.getProbabilityMass(k)
                            .setScale(5, RoundingMode.HALF_UP));
        }
        
        System.out.println();
        System.out.println("Poisson:");
        
        BigDecimal lambda = 
                binomial.getSuccessProbability()
                        .multiply(new BigDecimal(binomial.n()));
        
        PoissonDistribution poisson = new PoissonDistribution(lambda);
        
        for (int k = 0; k <= 5; ++k) {
            System.out.print(k + ": ");
            
            System.out.println(
                    poisson.getProbabilityMass(k)
                           .setScale(5, RoundingMode.HALF_UP));
        }
        
        System.out.println();
        System.out.println("Lambda = " + lambda);
        System.out.println();
        
        BigDecimal result = BigDecimal.ONE;
        
        for (int k = 0; k < 5; ++k) {
            result = result.subtract(poisson.getProbabilityMass(k));
        }
        
        System.out.println("P(Y >= 5) = " + result);
    }
    
    public static void main(String[] args) {
        tehtava1();
    }
}