i/Discrete_probability_distribution" target="_top">discrete
        distributions</a>, including the binomial, negative binomial, Poisson
        &amp; Bernoulli, are all mathematically defined as discrete functions: only
        integral values of the <a href="http://en.wikipedia.org/wiki/Random_variate" target="_top">random
        variate</a> are envisaged and the functions are only defined at these
        integral values. However because the method of calculation often uses continuous
        functions