Subversion Repositories wimsdev

!goto $wims_read_parm

:def
title=Data median
synonyme=statistic median, median of statistics
input=data1d
!exit

:proc

cnt=!itemcnt $formula
fml=
!for i=1 to $cnt
 t=!item $i of $formula
 fml=!append item $[$t] to $fml
!next i
fml=!sort numeric item $fml
!if $[$cnt%2]=1
 result=!item $[($cnt+1)/2] of $fml
!else
 t1=!item $[$cnt/2] of $fml
 t2=!item $[$cnt/2+1] of $fml
 result=$[($t1+$t2)/2]
!endif

!exit

:output

<center>
Median =
!htmlmath $result
</center> <p>
Data: $cnt numbers { $formula }
<p>
The <em>median</em> of sorted data {<i>x</i><sub>1</sub>,
<i>x</i><sub>2</sub>, ..., <i>x<sub>n</sub></i>} is equal to
!set ins_align=middle
!instex $$$$ {x_n+x_{n+1}\over 2} $$$$
 when <i>n</i> is even, or to <i>x</i><sub>(<i>n</i>+1)/2</sub> 
when <i>n</i> is odd.

!exit