🚀 go-pugleaf

Hello, 

In preparing a class example we found out that in computing quartiles
S-plus uses different methods under different commands. The method
used in the commands "summary" or "quantile" is different from the 
one used to compute quartiles for a boxplot in the command "boxplot".
We know which method is used in each case. Does anyone know the reason
for this difference.

Below is the illustration of this

>X      (The data)

  24  11 107  18  29  49  94  12  16  22 141  18  21  13  11

>summary(X)

 Min. 1st Qu. Median  Mean 3rd Qu. Max. 
   11    14.5     21 39.07      39  141

>A <- boxplot(X, plot=F)
>A

$stats:
     [,1] 
[1,]   94
[2,]   49  <-- 3rd Qu. 
[3,]   21  
[4,]   13  <-- 1st Qu.
[5,]   11

$n:
[1] 15


$out:
[1] 107 141  <-- If the quartiles computed in "summary" were used
                 then 94 will also be out. 

$group:
[1] 1 1

Bye, Toufik.