Book Image

Clojure for Data Science

By : Henry Garner
Book Image

Clojure for Data Science

By: Henry Garner

Overview of this book

Table of Contents (18 chapters)
Clojure for Data Science
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface
Index

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...