/** Creating a {@link FDistribution} with basic parameters */
  @Test
  public void testCreate() {
    val probability =
        FDistribution.<Character>builder()
            .denominatorDegreesOfFreedom(10.0)
            .numeratorDegreesOfFreedom(10.0)
            .build();

    assertThat(probability, is(not(nullValue())));
  }
 /** Creating with null denominator fails */
 @Test(expected = NullPointerException.class)
 public void testCreateFailNullNumeratorDegreesOfFreedom() {
   FDistribution.<Character>builder().denominatorDegreesOfFreedom(10.0).build();
 }