USING: kernel math sequences ;
: mean ( seq -- n )
- #! arithmetic mean, sum divided by length
+ #! arithmetic mean, sum divided by length
[ sum ] keep length / ;
: geo-mean ( seq -- n )
- #! geometric mean, nth root of product
- [ product ] keep length swap nth-root ;
+ #! geometric mean, nth root of product
+ [ product ] keep length swap nth-root ;
: median ( seq -- n )
- #! middle number if odd, avg of two middle numbers if even
+ #! middle number if odd, avg of two middle numbers if even
number-sort dup length dup even? [
- 1+ 2 /i dup 1- rot [ nth ] keep swapd nth + 2 /
- ] [
- 2 / swap nth
- ] if ;
+ 1+ 2 /i dup 1- rot [ nth ] keep swapd nth + 2 /
+ ] [
+ 2 / swap nth
+ ] if ;
: range ( seq -- n )
- #! max - min
- number-sort [ pop ] keep first - ;
+ #! max - min
+ number-sort [ pop ] keep first - ;
: var ( seq -- )
- #! variance, normalize by N-1
- dup length 1- dup 0 = [
- 0 2nip
- ] [
- swap [ mean ] keep [ over - sq ] map sum nip swap /
- ] if ;
+ #! variance, normalize by N-1
+ dup length 1- dup 0 = [
+ 0 2nip
+ ] [
+ swap [ mean ] keep [ over - sq ] map sum nip swap /
+ ] if ;
: std
- #! standard deviation, sqrt of variance
- var sqrt ;
+ #! standard deviation, sqrt of variance
+ var sqrt ;