[R] Dúvida função Anova pacote car - Medidas repetidas

[Rui Barradas]

Hello,

Yes, your Spanish is close enough to Portuguese for you to understand it.
I thought it was homework and didn't read untill the end. Apologies to 
Diego, and thanks to John.

Rui Barradas
Em 05-10-2012 22:48, John Fox escreveu:
> Dear Diego,
>
> This is close enough to Spanish for me to understand it (I think).
>
> Using Anova() in the car package for repeated-measures designs requires a
> multivariate linear model for all of the responses, which in turn requires
> that the data set be in "wide" format, with each response as a variable. In
> your case, there are two crossed within-subjects factors and no
> between-subjects factors. If this understanding is correct (but see below),
> then you could proceed as follows, where the crucial step is reshaping the
> data from "long" to "wide":
>
> ------------- snip --------------
>
> Pa2$type.day <- with(Pa2, paste(Type, Day, sep="."))
> (Wide <- reshape(Pa2, direction="wide", v.names="logbiovolume",
> idvar="Replicate", timevar="type.day", drop=c("Type", "Day")))
>
> day <- ordered(rep(c(0, 2, 4), each=2))
> type <- factor(rep(c("c", "t"), 3))
> (idata <- data.frame(day, type))
>
> mod <- lm(cbind(logbiovolume.c.0, logbiovolume.t.0, logbiovolume.c.2,
> logbiovolume.t.2, logbiovolume.c.4, logbiovolume.t.4) ~ 1, data=Wide)
>
> Anova(mod, idata=idata, idesign=~day*type)
>
> ------------- snip --------------
>
> This serves to analyze the data that you showed; you'll have to adapt it for
> the full data set.
>
> I'm assuming that the "replicates" are independent units, and that the
> design is therefore entirely within replicate. If that's wrong, then the
> analysis I've suggested is also incorrect.
>
> I hope this helps,
>   John
>
> -----------------------------------------------
> John Fox
> Senator McMaster Professor of Social Statistics
> Department of Sociology
> McMaster University
> Hamilton, Ontario, Canada
>
>
>
>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
>> On Behalf Of Diego Pujoni
>> Sent: Friday, October 05, 2012 9:57 AM
>> To: r-help at r-project.org
>> Subject: [R] Dúvida função Anova pacote car - Medidas repetidas
>>
>> Ola pessoal, estou realizando uma ANOVA com medidas repetidas e estou
>> utilizando a fungco "Anova" do pacote "car".
>>
>> Medi o biovolume de algas a cada dois dias durante 10 dias (no banco de
>> dados abaixo ss coloquei ati o 40 dia). Tenho 2 tratamentos ("c","t") e
>> o
>> experimento foi realizado em triplicas ("A","B","C").
>>
>>> Pa2
>>     Day Type Replicate logbiovolume
>> 1    0    c         A        19.34
>> 2    0    c         B        18.27
>> 3    0    c         C        18.56
>> 4    0    t         A        18.41
>> 5    0    t         B        18.68
>> 6    0    t         C        18.86
>> 7    2    c         A        18.81
>> 8    2    c         B        18.84
>> 9    2    c         C        18.52
>> 10   2    t         A        18.29
>> 11   2    t         B        17.91
>> 12   2    t         C        17.67
>> 13   4    c         A        19.16
>> 14   4    c         B        18.85
>> 15   4    c         C        19.36
>> 16   4    t         A        19.05
>> 17   4    t         B        19.09
>> 18   4    t         C        18.26
>> .
>> .
>> .
>>
>> Pa2.teste = within(Pa2,{group = factor(Type)
>>                     time = factor(Day)
>>                     id = factor(Replicate)})
>> matrix =
>> with(Pa2.teste,cbind(Pa2[,VAR][group=="c"],Pa2[,VAR][group=="t"]))
>> matrix
>>         [,1]  [,2]
>>   [1,] 19.34 18.41
>>   [2,] 18.27 18.68
>>   [3,] 18.56 18.86
>>   [4,] 18.81 18.29
>>   [5,] 18.84 17.91
>>   [6,] 18.52 17.67
>>   [7,] 19.16 19.05
>>   [8,] 18.85 19.09
>>   [9,] 19.36 18.26
>> [10,] 19.63 18.96
>> [11,] 19.94 18.06
>> [12,] 19.54 18.37
>> [13,] 19.98 17.96
>> [14,] 20.99 17.93
>> [15,] 20.45 17.74
>> [16,] 21.12 17.60
>> [17,] 21.66 17.33
>> [18,] 21.51 18.12
>>   model <- lm(matrix ~ 1)
>>   design <- factor(c("c","t"))
>>
>>   options(contrasts=c("contr.sum", "contr.poly"))
>>   aov <- Anova(model, idata=data.frame(design), idesign=~design,
>> type="III")
>>   summary(aov, multivariate=F)
>>
>> Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
>>
>>                   SS num Df Error SS den Df         F    Pr(>F)
>> (Intercept) 12951.2      1   6.3312     17 34775.336 < 2.2e-16 ***
>> design         19.1      1  17.3901     17    18.697 0.0004606 ***
>> ---
>> Signif. codes:  0 *** 0.001 ** 0.01 * 0.05 . 0.1   1
>>
>>
>> O problema i que eu acho que esta fungco nco esta levando em
>> consideragco
>> os dias, nem as riplicas. Como fago para introduzir isto na analise.
>> Vocjs
>> conhecem alguma fungco correspondente nco paramitrica para este teste?
>> Tipo
>> um teste de Friedman com dois grupos (tratamento e riplica) e um bloco
>> (tempo)?
>>
>> Muito Obrigado
>>
>>                                                 Diego PJ
>>
>> 	[[alternative HTML version deleted]]
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