(define (min-list l)
  (apply min l))

(define (max-list l)
  (apply max l))

(define (mean-list l)
  (/ (apply + l) (length l)))

(define (median l)
  (list-ref (sort l <) (quotient (length l) 2)))

(define (stdev l)
  (let* ((sum.sqr (apply + (map (lambda (x) (* x x)) l)))
	 (mean (mean-list l))
	 (n (length l)))
    (sqrt (- (/ sum.sqr n) (* mean mean)))))
	 
	 

(define (stats l)
  (list 'min (min-list l)
	'median (median l)
	'max (max-list l)
	'mean (mean-list l)
	'stdev (stdev l)))