gistfile1.clj

#!/usr/bin/env clj

(ns ols)
  
(defn sum [x]
  (reduce + 0 x))
  
(defn multsum [x y]
  (loop [xdata x 
        ydata y 
        index 0 
        total 0]
    (if (seq xdata)
      (recur (rest xdata) 
             (rest ydata) 
             (inc index) 
             (+ total (* (first xdata) (first ydata))))
      total)))
      
(defn olsbeta [x y]
  (/ (- (* (count x) (multsum x y)) (* (sum x) (sum y)))
     (- (* (count x) (multsum x x)) (* (sum x) (sum x)))
    ))

(defn yintercept [x y]
  (- (* (/ 1 (count x)) (sum y)) (* (olsbeta x y) (* (/ 1 (count x)) (sum x)))))

;; test

(def x [1.47 1.50 1.52 1.55 1.57 1.60 1.63 1.65 1.68 1.70 1.73 1.75 1.78 1.80 1.83])
(def y [52.21 53.12 54.48 55.84 57.20 58.57 59.93 61.29 63.11 64.47 66.28 68.10 69.92 72.19 74.46])

(prn (apply str ["y = " (olsbeta x y) "*x + " (yintercept x y)]))