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; Compulsory Exercise 0. Complete by Thursday 16th October at 13.00 hours
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;;; define the following functions

(define (min-list l)
  'define-me); deliver the smallest element in list l; hint, look at apply

(define (median-list l)
 'define-me) ; deliver the median of the list l
             ; where median is the value that splits the population
             ; in half. Note: you might use functions sort and list-ref

(define (max-list l)
 'define-me); deliver the largest element in list l

(define (mean-list l)
 'define-me); deliver the mean of the list

(define (stdev-list l)
  'define-me); deliver the standard deviation of the list l

(define (stats l)
  (list (min-list l) (median-list l) (max-list l)
	(mean-list l) (stdev-list l))); deliver a 5-tuple statistic

;;; Test out your functions on randomly generated data read from file
;;; That is use function write-random-data to write random numbers to
;;; a file, then use file->list to get that data, then do stats on it.
;;; Se io.scm for these functions

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;;; (much) more advanced and optional


(define (ps s)
  'define-me); where s is a set of values (as a list)
             ; sample output is as below
;> (ps '(1 2 3))
;Evaluation took 0 mSec (0 in gc) 173 cells work, 37 bytes other
;((1 2 3) (1 2) (1 3) (1) (2 3) (2) (3) ())
;> (ps '(send more money))
;Evaluation took 0 mSec (0 in gc) 158 cells work, 47 bytes other
;((send more money) (send more) (send money) (send) 
; (more money) (more) (money) ())
;> 

(define (cp lists)
  'define-me) ; where lists is a list of lists
              ; sample output below
;> (cp '((1 2) (a b)))
;Evaluation took 0 mSec (0 in gc) 140 cells work, 35 bytes other
;((1 a) (1 b) (2 a) (2 b))
;> (cp '((1 2) (a b) (dog cat mouse)))
;Evaluation took 0 mSec (0 in gc) 343 cells work, 49 bytes other
;((1 a dog) (1 a cat) (1 a mouse) 
; (1 b dog) (1 b cat) (1 b mouse) 
; (2 a dog) (2 a cat) (2 a mouse) 
; (2 b dog) (2 b cat) (2 b mouse))