[R] pairwise.t.test: empty p-table

[Thomas Hoffmann]

Hi list-members

can anybody tell me why

 > pairwise.t.test(val, fac)

produces an empty p-table. As shown below:


        Pairwise comparisons using t tests with pooled SD

data:  val and fac

       AS AT Fhh Fm Fmk Fmu GBS Gf HFS Hn jAL Kol R_Fill
AT     -  -  -   -  -   -   -   -  -   -  -   -   -    
Fhh    -  -  -   -  -   -   -   -  -   -  -   -   -    
Fm     -  -  -   -  -   -   -   -  -   -  -   -   -    
Fmk    -  -  -   -  -   -   -   -  -   -  -   -   -    
Fmu    -  -  -   -  -   -   -   -  -   -  -   -   -    
GBS    -  -  -   -  -   -   -   -  -   -  -   -   -    
Gf     -  -  -   -  -   -   -   -  -   -  -   -   -    
HFS    -  -  -   -  -   -   -   -  -   -  -   -   -    
Hn     -  -  -   -  -   -   -   -  -   -  -   -   -    
jAL    -  -  -   -  -   -   -   -  -   -  -   -   -    
Kol    -  -  -   -  -   -   -   -  -   -  -   -   -    
R_Fill -  -  -   -  -   -   -   -  -   -  -   -   -    
Sa     -  -  -   -  -   -   -   -  -   -  -   -   -    


However val and fac do have the same length and are not empty:
 > summary(fac)
    AS     AT    Fhh     Fm    Fmk    Fmu    GBS     Gf    HFS     Hn    
jAL    Kol R_Fill     Sa
    50     14      7     35     14     25     59     51     90     
65     12     26     96     26
 > summary(val)
    Min.  1st Qu.   Median     Mean  3rd Qu.     Max.     NA's
  0.0000   0.1744   0.6395   2.1540   1.7440  40.1200 223.0000

Thanks in advamce
Thomas H.