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List:       r-help
Subject:    Re: [R] A simple question about summary.glm
From:       michal33 <michal_sa () hotmail ! com>
Date:       2007-07-31 21:48:22
Message-ID: 11935815.post () talk ! nabble ! com
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Thanks Uwe for your question,

Yesterday I found out what I wanted to know: 
In the summary table the values refer to the different of each treatment to
the first treatment alphabetical (in my case it was the control group and
therefore served as Tukey test, which is what I wanted in the first place).



Uwe Ligges wrote:
> 
> 
> 
> michal33 wrote:
> > Hello,
> > 
> > I am new to R and have tried to search similar questions but could not
> > find
> > exactly what I am looking for, but I apologize if the question was
> > already
> > asked.
> > 
> > I have 10 different treatments and want to know whether they affect the
> > sex
> > ratios of insect emergence. After running the glms I got this table:
> > 
> > Df Deviance Resid. Df Resid. Dev      F   Pr(>F)   
> > NULL                    133     9250.3                   
> > sex    1    481.5       132     8768.9 7.7212 0.006314 **
> > trt    9   1099.1       123     7669.7 1.9585 0.049780 * 
> > 
> > But now I would like to know WHICH of the treatments was significant. I
> > tried to use Tukey test but for some reason it does not work. 
> > My question is:
> > I used the following function: 
> > > summary(file.name, corr=F)
> > and got the following table:
> > Deviance Residuals: 
> > Min       1Q   Median       3Q      Max  
> > -14.118   -4.808   -1.466    2.033   33.882  
> > Coefficients:
> > Estimate Std. Error   t value Pr(>|t|)    
> > (Intercept)  8.696e+00  1.893e+00     4.594 1.06e-05 ***
> > sexm        -3.791e+00  1.364e+00    -2.779  0.00631 ** 
> > trtccc      -1.050e+00  4.325e+00    -0.243  0.80859    
> > trtcga3      2.450e+00  4.325e+00     0.566  0.57211    
> > trtcga4     -2.300e+00  4.325e+00    -0.532  0.59584    
> > trtg         1.550e+00  2.497e+00     0.621  0.53593    
> > trtga4      -5.550e+00  4.325e+00    -1.283  0.20183    
> > trtp         5.422e+00  2.566e+00     2.113  0.03658 *  
> > trtpg       -1.850e+00  2.497e+00    -0.741  0.46019    
> > trtw        -3.634e-17  2.497e+00 -1.46e-17  1.00000    
> > trtwg       -3.750e+00  2.497e+00    -1.502  0.13573    
> > 
> > What do the stars  mean?
> 
> 
> Well, you omitted the last lines from the output which include:
> 
> Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
> 
> 
> i.e. *** for values < 0.001; * for values in [0.01, 0.05) etc.
> 
> Uwe Ligges
> 
> 
> 
> Is it the same as Tukey test that tells me which
> > treatment is different from which? i.e. is trtp (with *) significantly
> > different to the control (which, by the way do not appear in this list
> > and I
> > do not know why)? 
> > 
> > Thanks
> > Michal
> > 
> > 
> 
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 

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