ProbabilityCalculator

import java.lang.Math;


public class ProbabilityCalculator {

    //calculate probability without replacement with two quantities and n of the first quantity
    private float probabilityWithoutReplacement(int k1, int k2, int n){
        float probability = 1;

        while(n > 0){
            probability *= (float) k1/(k1+k2);
            n--;
            k1--;
        }

        return probability;
    }


    //calculate the probability of exactly k successes in n trials given probability p
    private float binomialProbability(int n, float p, int k){
        float probability = 0;
        probability = binomialCoefficient(n,k)* ((float) Math.pow(((double) p),
                ((double) k))) * ((float) Math.pow((double)(1-p), ((double)(n-k)) ));
        return probability;
    }

    /*
     * Calculate the binomial coefficient using the formula n!/(k!(n-k)!)
     */
    private float binomialCoefficient(int n, int k){
        float coefficient = 0;
        coefficient = (float) factorial(n)/(factorial(k)*factorial(n-k));
        return coefficient;
    }

    //Calculate the factorial of an integer
    private int factorial(int factor){
        int product = 1;
        while(factor > 0){
            product *= factor;
            factor--;
        }
        return product;
    }


    //Only for testing purposes. Prints the probability of getting 5 successes
    //when drawing 5 times replacing and constant probability of .5
    public static void main(String[] args){
        ProbabilityCalculator pc = new ProbabilityCalculator();
        System.out.printf("Med tilbakelegging: P= %.02f%%%n", (pc.binomialProbability(2,
                pc.probabilityWithoutReplacement(4, 6, 1), 2) * 100)); //6 sorte, 4 hvite
        System.out.printf("Uten tilbakelegging: P= %.02f%%%n", (pc.probabilityWithoutReplacement(6, 4, 2)) * 100);

    }
}