[R] Anova

[Dani Valverde]

Hello,
I am trying to perform an ANOVA on a dataframe like this:
 
              ID Grup      ML              PC                  
mI                   Gly             Glx
X373.txt     1    1 0.004685889  0.05994939 0.004589104   0.007144027  
0.02042549
X373bis.txt  2    1 0.004685889   0.0599494 0.004589104   0.007144028   
0.0204255
X376.txt     3    1 0.007604898  0.07600049  0.01935247    0.01678972  
0.03363403
X392.txt     4    1 0.004982747  0.02760991  0.01855596    0.01413439  
0.02013267
X483.txt     5    1 0.009131522  0.02636227  0.02485232    0.01493074  
0.02532194
X520.txt     6    1 0.008553895  0.06304886  0.02490261    0.01907819  
0.03356447
X671.txt     7    1 0.008004383  0.05243909   0.0229447      0.024266  
0.03553224
X673A.txt    8    1  0.01306893  0.02799318  0.01155338   0.007668364  
0.02123958
X673B.txt    9    1 0.006099385   0.0516078  0.03099324    0.02664487  
0.03766267
X674.txt    10    1 0.005476397  0.04945545  0.01479742    0.01084873  
0.02307815
X681.txt    11    1 0.009807893  0.01680487 0.004524913   0.004705414 
0.008969453
X725.txt    12    1  0.01018343   0.0119391 0.007911063   0.008005791  
0.01014625
X746.txt    13    1 0.008864319  0.02484126  0.01198048    0.01276371  
0.01042683
X772.txt    14    1 0.005966057  0.07398342   0.0210399    0.01606057  
0.02932874
X814.txt    15    1  0.01350947   0.0317243 0.003234958   0.002958675 
0.005194511
X835.txt    16    1 0.005509359  0.02670237  0.07425323    0.04095533    
0.031017
X847.txt    17    1 0.004784228  0.05349206  0.01183679    0.01230316  
0.03073348
X851.txt    18    1 0.004395889  0.03812635  0.01998653    0.02165763  
0.02074277
X865.txt    19    1 0.001514055  0.07128447   0.0106887    0.00802192  
0.01478855
X878.txt    20    1 0.003693918  0.03864821  0.01571797    0.01972568    
0.022711
et2029.txt  21    1  0.05204285  0.03769878  0.03168799    0.03631842  
0.02732589
et2348.txt  22    1  0.01407517  0.01679014 0.004900163   0.004243802  
0.01052361

The table is truncated because it's very big, but it has 3 different 
groups (Grup variable) and it's called GBM.
I try to use the command:

aov(GBM$Grup~GBM$ML,data=GBM)

But I get this error:

/Error in storage.mode(y) <- "double" :
  invalid to change the storage mode of a factor
In addition: Warning message:
In model.response(mf, "numeric") :
  using type="numeric" with a factor response will be ignored/

How can I solve this?
Best,

Dani

-- 
Daniel Valverde Saubí

Grup de Biologia Molecular de Llevats
Facultat de Veterinària de la Universitat Autònoma de Barcelona
Edifici V, Campus UAB
08193 Cerdanyola del Vallès- SPAIN

Centro de Investigación Biomédica en Red
en Bioingeniería, Biomateriales y
Nanomedicina (CIBER-BBN)

Grup d'Aplicacions Biomèdiques de la RMN
Facultat de Biociències
Universitat Autònoma de Barcelona
Edifici Cs, Campus UAB
08193 Cerdanyola del Vallès- SPAIN
+34 93 5814126