Independent samples of t-tests are the most common sort of statistical analysis, which provide a very flexible and generic way of comparing whether two samples represent the same or different population. However, in cases where the population mean is already known, there is an even simpler test represented by s/simple-t-test.
We pass a sample and a population mean to test against with the :mu keyword. So, if we simply want to see whether our new site is significantly different from the previous population mean dwell time of 90s, we can run a test like this:
(defn ex-2-18 []
(let [data (->> (load-data "new-site.tsv")
(:rows)
(group-by :site)
(map-vals (partial map :dwell-time)))
b (get data 1)]
(clojure.pprint/pprint (s/t-test b :mu 90))))
;; {:p-value 0.13789520958229406,
;; :df 15,
;; :n2 nil,
;; :x-mean 122.0,
;; :y-mean nil,
;; :x-var 6669.866666666667,
;; :conf-int [78.48152745280898 165...
