Plotting probability densities

In addition to using jStat to generate samples from the exponential distribution, we'll also use it to calculate the probability density for the t-distribution. We can construct a simple function to wrap the jStat.studentt.pdf(t, df) function, providing the correct t-statistic and degrees of freedom to parameterize the distribution:

(defn pdf-t [t & {:keys [df]}]
  (js/jStat.studentt.pdf t df))

An advantage of using ClojureScript is that we have already written the code to calculate the t-statistic from a sample. The code, which worked in Clojure, can be compiled to ClojureScript with no changes whatsoever:

(defn t-statistic [test {:keys [mean n sd]}]
  (/ (- mean test)
     (/ sd (Math/sqrt n))))

To render the probability density, we can use B1's c/function-area-plot. This will generate an area plot from the line described by a function. The provided function simply needs to accept an x and return the corresponding y.

A slight complication is that the value...