Re: [R] two-way anova help

2011-09-27 Thread S Ellison
bout statistics is about as sensible as taking a statistician's advice about chemistry - the mileage can vary. S Ellison > -Original Message- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Austin Paul > Sent: 27 September 2011 0

Re: [R] two-way anova help

2011-09-27 Thread Indrajit Sengupta
if this is making sense to you. Regards, Indrajit From: Austin Paul Cc: "r-help@r-project.org" Sent: Tuesday, September 27, 2011 12:30 PM Subject: Re: [R] two-way anova help Hi Indrajit and Bert,   I really appeciate your help.  I have coded as

Re: [R] two-way anova help

2011-09-27 Thread Austin Paul
lication. Your model form will remain the same. > > Regards, > Indrajit > > -- > *From:* Austin Paul > *To:* Indrajit Sengupta > *Cc:* "r-help@r-project.org" > *Sent:* Tuesday, September 27, 2011 10:57 AM > *Subject:* Re: [R] t

Re: [R] two-way anova help

2011-09-26 Thread Bert Gunter
Tanks are the experimental unit, fishes within tanks are repeated measures of the treatment, there is no "nesting" of replicates. You can analyze the 45 x 50 individual data values by repeated measures (mixed effects models) or by summarizing the 50 measurements per tank=treatment into a single val

Re: [R] two-way anova help

2011-09-26 Thread Indrajit Sengupta
___ To: Austin Paul Cc: "r-help@r-project.org" Sent: Tuesday, September 27, 2011 12:10 PM Subject: Re: [R] two-way anova help Hi Paul, There should not be any problem. Here is how I visualize the data table looks like: Obs Male_type   Female_type  Response 1 1 1 34 2 1 1 44

Re: [R] two-way anova help

2011-09-26 Thread Indrajit Sengupta
model form will remain the same. Regards, Indrajit From: Austin Paul Cc: "r-help@r-project.org" Sent: Tuesday, September 27, 2011 10:57 AM Subject: Re: [R] two-way anova help Hi, Yes.  As I explained, the three male and three female types were

Re: [R] two-way anova help

2011-09-26 Thread Austin Paul
Hi, Yes. As I explained, the three male and three female types were crossed in all combinations (9 ways). For each of the 9 types, I have *5 replicate tanks* (45 total tanks). And from each of the 45 tanks I have 50 observations for size. So the 5 replicates are somehow nested within the two-w

Re: [R] two-way anova help

2011-09-26 Thread Indrajit Sengupta
Can you explain what do you mean by "5 replicate tanks"? Doing a two way anova is very simple in R. You would need to fit a linear model (lm function). Eg.: > model <- lm(y ~ male + female + male:female, data =) Regards, Indrajit From: Austin Paul To: r-

Re: [R] Two-way ANOVA gives different results using anova(lm()) than doing it by hand

2009-07-08 Thread Zhiliang Ma
the following works. i don't exactly what happens here. I guess "lm" might treat S1 and S2 as quantitative variables, not qualitative variables. cheers, Zhiliang S1 <- as.character(Data[,1]) S1 <- as.factor(S1) S2 <- as.character(Data[,2]) S2 <- as.factor(S2) data <- data.frame(S1=S1, S2=S2, ExM=

Re: [R] Two-way ANOVA gives different results using anova(lm()) than doing it by hand

2009-07-08 Thread Marc Schwartz
On Jul 8, 2009, at 12:11 PM, Greg Snow wrote: Well, since we don't have Data.txt it is kind of hard for us to replicate what you have done. Here goes a guess as to what the problem may be. Have you told R anywhere that S1 and S2 are factors with 6 levels rather than numeric vectors? Or are

Re: [R] Two-way ANOVA gives different results using anova(lm()) than doing it by hand

2009-07-08 Thread Greg Snow
Well, since we don't have Data.txt it is kind of hard for us to replicate what you have done. Here goes a guess as to what the problem may be. Have you told R anywhere that S1 and S2 are factors with 6 levels rather than numeric vectors? Or are you just hoping that the computer can read your mi

Re: [R] Two-way Anova

2009-05-12 Thread Mike Lawrence
Using traditional ANOVA, you'd have to drop either cases or time points with missing data. Using linear mixed effects analysis, you'd be able to use all the data. LME also has the benefit of *not* assuming sphericity, which is good for data like yours (many measures across few cases) where the trad

Re: [R] Two Way ANOVA

2008-03-19 Thread Daniel Malter
Hi, your post is hardly readable because it is so spread out over several pages. Can you repost it? Besides that I do not understand your question fully. The y is your dependent variable and as it looks the A*B would be Sulfur*Nitrogen if these are your variable names. You can also take a look

Re: [R] Two Way ANOVA

2008-02-28 Thread Peter Alspach
Keith Try names(sumpcf) or str(sumpcf). That should help you find what you want. Incidentally, simply summary(pcf.aov) will do - R uses the appropriate method based on the type of object. HTH Peter Alspach > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTE