Two ways of making graph, fixed bug with thresholds

src/main/java/Equations.java

@@ -1,6 +1,25 @@
+import java.math.BigInteger;
+
 public abstract class Equations {
 
     public static double pValue(Integer w, Integer w_a, Integer w_b, Integer w_ab) {
         return 1.0;
     }
+
+    private static double probPairedByChanc(Integer w, Integer w_a, Integer w_b, Integer w_ab){
+        return 1.0;
+    }
+
+    /*
+     * This works because nC(k+1) = nCk * (n-k)/(k+1)
+     * Since nC0 = 1, can start there and generate all the rest.
+     */
+     public static BigInteger choose(final int N, final int K) {
+         BigInteger nCk = BigInteger.ONE;
+         for (int k = 0; k < K; k++) {
+             nCk = nCk.multiply(BigInteger.valueOf(N-k))
+                 .divide(BigInteger.valueOf(k+1));
+         }
+         return nCk;
+     }
 }