babbage-2.clj

;; Simple mean function.
#> (defn compute-mean [xs] (/ (reduce + xs) (count xs)))

;; Check the average spend for firefox.
#> (->> (all-visitors) 
        (filter #(-> % :browser (= :firefox))) 
        (keep :spend) 
        compute-mean)
100.2

;; And now for chrome.
#> (->> (all-visitors) 
        (filter #(-> % :browser (= :chrome))) 
        (keep :spend) 
        compute-mean)
112.9