Dear list,

I have been searching for a week to fit a simple linear model to my data. I
have looked into the previous posts but I haven't found anything relevant to
my problem. I guess it is something simple...I just cannot see it.
I have the following data frame, named "data", which is a subset of a
microarray experiment. The columns are the samples and the rows are the
probes. I binded the first line, called "norm", which represents the
estimated output. I want to create a linear model which shows the
relationship between the gene expressions (rows) and the output (norm).

 *data*
            GSM276723.CEL GSM276724.CEL GSM276725.CEL GSM276726.CEL
norm             0.897000      0.590000      0.683000      0.949000
206427_s_at      5.387205      6.036506      8.824783     10.864122
205338_s_at      6.454779     13.143095      6.123212     12.726562
209848_s_at      6.703062      7.783330     12.175654      9.339651
205694_at        5.894131      5.794516     12.876555     11.534664
201909_at       12.616538     12.913255     12.275182     12.767743
208894_at       13.049286      9.317874     12.873516     13.527182
216512_s_at      6.324789     12.783791      6.216932     12.013404
205337_at        6.175940     12.158796      6.117519     12.041078
201850_at        6.633013      6.465900      6.535434      7.749985
210982_s_at     12.444791      8.597388     12.197696     12.963449
            GSM276727.CEL GSM276728.CEL GSM276729.CEL GSM276731.CEL
norm             0.302000      0.597000      0.270000      0.530000
206427_s_at      5.690357      8.014055     13.034753      5.493977
205338_s_at      5.757048      7.706341     13.258410      5.562588
209848_s_at      6.461028      7.036515     13.633649      5.874098
205694_at        5.519552      5.297107      6.498811      5.146150
201909_at       12.814454     11.592632      6.594229      6.650796
208894_at       13.835359     13.028096      5.839909      6.045578
216512_s_at      6.033096      7.273650     12.669054      5.946932
205337_at        5.879028      7.381713     12.633829      5.379559
201850_at        9.684397      6.560014      8.523229      6.573052
210982_s_at     13.342729     12.470517      5.903681      5.658115
            GSM276732.CEL GSM276735.CEL GSM276736.CEL GSM276737.CEL
norm              0.43400      0.647000      0.113000      1.000000
206427_s_at      12.80257      5.645002      6.519554     13.572480
205338_s_at      13.38057      5.804107     11.090690     14.024922
209848_s_at      13.27718      6.490851      9.784199     14.101162
205694_at        11.37717      5.802105      7.944963     14.060492
201909_at        13.24126     12.263899     12.578315      6.443491
208894_at        12.29916      7.563361      9.971493      7.094214
216512_s_at      13.00303      5.905789     10.512761     13.647573
205337_at        12.63560      5.430138     10.707242     13.020312
201850_at        12.71874      6.275480      6.987962     12.354580
210982_s_at      11.53559      7.225199      9.322706      6.617615
            GSM276738.CEL GSM276739.CEL GSM276740.CEL GSM276742.CEL
norm              0.35700      0.967000      0.823000      1.000000
206427_s_at      13.33764     13.607918     13.190551     12.387189
205338_s_at      13.65492     12.812950     12.237476     12.912605
209848_s_at      13.48525     13.435389     13.851347     12.540495
205694_at         7.70928     10.045331     13.391456     11.103841
201909_at        12.47093     11.937344      6.631023      7.160071
208894_at        12.20508      8.892181      6.478889      5.927860
216512_s_at      13.42313     12.151691     11.620552     12.341763
205337_at        12.67544     12.036528     11.641203     12.275845
201850_at        11.85481     13.172666     12.964316     12.156142
210982_s_at      11.49940      8.380404      6.121762      5.921634
            GSM276743.CEL GSM276744.CEL GSM276745.CEL GSM276747.CEL
norm             0.899000      0.927000      0.754000      0.437000
206427_s_at     12.665097     12.604673     11.446630     13.000295
205338_s_at     13.261141     12.448096     13.185698     12.510952
209848_s_at     13.396711     13.882529     13.040600     12.984137
205694_at       10.888474      7.094063      8.630120     12.321685
201909_at       12.100560      6.666787     12.330600      6.572282
208894_at        7.741437      8.348155     10.106442      6.009902
216512_s_at     12.830373     11.504074     12.300163     11.525958
205337_at       12.264569     11.676281     11.940917     11.618351
201850_at       11.055564     12.202366      7.327056     12.853055
210982_s_at      7.285289      8.129298      9.577032      5.924993
            GSM276748.CEL GSM276752.CEL GSM276754.CEL GSM276756.CEL
norm             0.321000      0.620000      0.155000      0.946000
206427_s_at      9.081283     11.446978      8.191261     13.192507
205338_s_at     13.737773     13.698520     12.983830     10.948681
209848_s_at     13.234025     12.956672     10.644642     13.176656
205694_at        7.953865      7.397013      7.170732     13.618932
201909_at       12.533684      7.049442      6.804030      7.135974
208894_at       11.868729      8.558455      6.629858      6.850639
216512_s_at     13.589290     12.781853     12.060414     10.143297
205337_at       13.084386     12.442617     12.104849     10.364035
201850_at        6.615453      8.104145      7.058739      6.514298
210982_s_at     11.058085      7.891520      6.516261      6.532226
            GSM276758.CEL GSM276759.CEL
norm             0.767000      0.218000
206427_s_at      5.742074     11.232337
205338_s_at      6.375289     13.406557
209848_s_at      6.226996      6.835458
205694_at        5.864042     11.218719
201909_at        6.907489      7.316435
208894_at       12.596987     12.408412
216512_s_at      6.308256     12.318892
205337_at        6.063775     12.389912
201850_at        6.816491      6.602764
210982_s_at     11.985288     11.853911

*What I did is the following:*
>fm1=as.formula((norm) ~ "206427_s_at" + "205338_s_at" + "209848_s_at" +
"205694_at" + "201909_at" + "208894_at" + "216512_s_at" + "205337_at" +
"201850_at" + "210982_s_at")
>lm1=lm(fm1,data1new)

And I receive the following error:
Error in terms.formula(formula, data = data) :
  invalid model formula in ExtractVars


*I have also tried:*
>cols=rownames(data3)  %%%%Where data3 is the same data frame with data
above, but without the "norm" row binded yet
thus: > cols
 [1] "206427_s_at" "205338_s_at" "209848_s_at" "205694_at"   "201909_at"
 [6] "208894_at"   "216512_s_at" "205337_at"   "201850_at"   "210982_s_at"

> lm1=lm(fm1,data1new)

and in this case Ireceive the following error:
Error in model.frame.default(formula = fm1, data = data1new,
drop.unused.levels = TRUE) :
variable lengths differ (found for 'cols')

Could anyone help me with this?

Thank you very much in advance,
Eleni

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