Comparisons with relative risk and odds

The preceding Incanter dataset is an easily comprehensible representation of our data, but to extract the numbers for each of the groups individually we'll want to store the data in a more readily accessible data structure. Let's write a function to convert the dataset to a series of nested maps:

(defn frequency-map [sum-column group-cols dataset]
  (let [f (fn [freq-map row]
            (let [groups (map row group-cols)]
              (->> (get row sum-column)
                   (assoc-in freq-map groups))))]
    (->> (frequency-table sum-column group-cols dataset)
         (:rows)
         (reduce f {}))))

For example, we can use the frequency-map function as follows to calculate a nested map of :sex and :survived:

(defn ex-4-3 []
  (->> (load-data "titanic.tsv")
       (frequency-map :count [:sex :survived])))

;; => {"female" {"y" 339, "n" 127}, "male" {"y" 161, "n" 682}}

More generally, given any dataset and sequence of columns...