Error message: attempt to set rownames on object with no dimensions

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?lme (at least the one in package nlme) seems not to mention that the 
response in 'fixed' must be a numeric variable, but it must (and a 
factor is not numeric).

If you want to use a binary response, you need to use other methods, 
and it would be better to ask on R-sig-mixed-models making clear what 
your aims actually are.

Hi there,

I am trying to analyze some data using the lme package.
Perhaps you mean the nlme package?
In my case there is a variable called Newmarker that can only take 2 values
(number 1 or number 2).
I have used the as.factor to remark this fact but an error message appears
stating: attempt to set rownames on object with no dimensions.

Here is the code I have used:

*Dataset <-   read.table("Data2.txt", header=TRUE, sep="", na.strings="NA",
dec=".", strip.white=TRUE)

Dataset$Newmarker <- as.factor(Dataset$Newmarker)

attach(Dataset)

lme.1 <- lme(Newmarker ~ Age, data=Dataset,  random= ~1|ID)

summary(lme.1)*

If I don't use the as.factor I have no problems but I don't think this is
the correct way to proceed... The other variables I use can have any value.

Can anybody help me please?

Thanking you in advance,

Regards,

Igor Blanco

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Hi there,

I am trying to analyze some data using the lme package.
In my case there is a variable called Newmarker that can only take 2  
values
(number 1 or number 2).
I have used the as.factor to remark this fact but an error message  
appears
stating: attempt to set rownames on object with no dimensions.

Here is the code I have used:

*Dataset <-   read.table("Data2.txt", header=TRUE, sep="",  
na.strings="NA",
dec=".", strip.white=TRUE)

Dataset$Newmarker <- as.factor(Dataset$Newmarker)
Why do you use as.factor? It's probably already a factor. What does  
str(Dataset) show?
attach(Dataset)
You do not need to do this, and it creates potential for confusion.  
The data= argument will allow the column names to be accessed by the  
lme() function.
lme.1 <- lme(Newmarker ~ Age, data=Dataset,  random= ~1|ID)

summary(lme.1)*

If I don't use the as.factor I have no problems but I don't think  
this is
the correct way to proceed... The other variables I use can have any  
value.

David Winsemius, MD
West Hartford, CT