Hi:
You might want to use a binomial generalized linear mixed model, for which
the
lme4 package and the functions lmer() and glmer() could come in handy. Since
there
is a dedicated list to mixed models, future questions on this particular
topic should
be sent there (subscribe to sig-mixed-models).
HTH,
Dennis
On Sun, Jan 24, 2010 at 2:26 PM, Marcelo Laia <marcelolaia@gmail.com>
wrote:
> Hi,
>
> I am trying to analyze a data set when nematodes were killed after a
> drug administration.
>
> We have counted the number of nematode died and the number of nematode
> survival at three time points.
>
> So, there are 100% died in some plot and could be found zero percent
> in another. Then, the data set have a lot of zeros.
>
> I have googled and found a lot of information. Moreover, my data isn't
> adjust to a normal distribution.
>
> I have transformed it to square root, but, due to zeros, it don't fit
> to a normal.
>
> The design is a split-plot. I divided a Petri dish in four parts and
> each day we measured one of they.
>
> Here is a sample of the data:
>
> trat rep time killed living percent.killed percent.living
> 1 1 48 8 6 57.14 42.86
> 1 2 48 17 15 53.13 46.88
> 1 3 48 6 4 60.00 40.00
> 1 1 72 17 15 53.13 46.88
> 1 2 72 24 33 42.11 57.89
> 1 3 72 11 0 100.00 0.00
> 1 1 96 18 28 39.13 60.87
> 1 2 96 19 6 76.00 24.00
> 1 3 96 9 10 47.37 52.63
> 2 1 48 7 2 77.78 22.22
> 2 2 48 10 4 71.43 28.57
> 2 3 48 8 2 80.00 20.00
> 2 1 72 5 2 71.43 28.57
> 2 2 72 14 13 51.85 48.15
> 2 3 72 30 1 96.77 3.23
> 2 1 96 2 6 25.00 75.00
> 2 2 96 11 15 42.31 57.69
> 2 3 96 3 2 60.00 40.00
> 3 1 48 8 8 50.00 50.00
> 3 2 48 6 7 46.15 53.85
> 3 3 48 0 2 0.00 100.00
> 3 1 72 3 3 50.00 50.00
> 3 2 72 5 1 83.33 16.67
> 3 3 72 18 10 64.29 35.71
> 3 1 96 4 0 100.00 0.00
> 3 2 96 0 0 0.00 0.00
> 3 3 96 18 19 48.65 51.35
>
> We have counted killed and living because free-living nematode
> reproduce very fast, so I need to know the number of living in the
> medium.
>
> What you suggest me for analyze this on R? What transformation I could do?
>
> There were a specific package for that?
>
> Have you did something like this?
>
> Thank you very much
>
> --
> Marcelo Luiz de Laia
> Lages - SC - Brazil
> Linux user number 487797
>
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