Diversity prediction theorem: Difference between revisions
→{{header|Racket}}
(→{{header|Racket}}: stub) |
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=={{header|Racket}}==
{{trans|Clojure}}
<lang racket></lang>▼
(define (mean l)
(/ (apply + l) (length l)))
(define (diversity-theorem truth predictions)
(define μ (mean predictions))
(define (avg-sq-diff a)
(mean (map (λ (p) (sqr (- p a))) predictions)))
(hash 'average-error (avg-sq-diff truth)
'crowd-error (sqr (- truth μ))
'diversity (avg-sq-diff μ)))
(println (diversity-theorem 49 '(48 47 51)))
(println (diversity-theorem 49 '(48 47 51 42)))</lang>
{{out}}
<pre>'#hash((average-error . 3) (crowd-error . 1/9) (diversity . 2 8/9))
'#hash((average-error . 14 1/2) (crowd-error . 4) (diversity . 10 1/2))</pre>
=={{header|Raku}}==
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