Clojure: Anonymous Function and its Shorthand

Just enough confusion to almost skip this part. But made it eventually. ?

(def sum #(reduce + %))
(def avg #(/ (sum %) (count %)))

(defn stats
  [numbers]
  (map #(% numbers) [sum count avg]))

(defn stats-long
  [numbers]
  (map
    (fn [f]
      (f numbers))
    [sum count avg]))

(stats [1 2 3])                                             ;=> (6 3 2)
(stats-long [1 2 3])                                        ;=> (6 3 2)

(stats [8 6 10 13 29])                                      ;=> (66 5 66/5)
(stats-long [8 6 10 13 29])                                 ;=> (66 5 66/5)