/** Plot the binomial function's density function and cumulative
    distribution function.
*/
use statistics.frink

println[binomialProbability[55,100,1/2]-binomialProbability[45,100,1/2]]

/** n is number of trials, p is probability of success on a single trial. */
plotBinomial[g is graphics, n, p] :=
{
   for k=0 to n
   {
      d = binomialDensity[k,n,p]
      pp = binomialProbability[k,n,p]
      g.fillRectSides[k/n,-d,(k+1)/n,0]
      g.line[k/n,-pp,(k+1)/n,-pp]
   }
}

g = new graphics
plotBinomial[g, 800, 1/2]
g.show[]