poissondist.js

function sFact(num)
{
    var rval=1;
    for (var i = 2; i <= num; i++)
        rval = rval * i;
    return rval;
}

function poisson(k, lambda) {
  return (Math.exp(-1*lambda) * Math.pow(lambda, k))/sFact(k);
}

function poissondist(min, max, lambda) {
    for (var i = min; i <= max; i++) {
        console.log("p(" + i + ", " + lambda + ") = " + poisson(i, lambda) );
    }
}