R help - May 2011 - likelihood ratio test

Dear R-help,
Can anybody tell me which R package has Lo-Mendell Rubin LR test and Bootstrap 
LR test to compare the model fit between k class and k+1 class model for Latent 
class analysis?
Thanks in advance,
 warn regards,Ms.Karunambigai M
PhD Scholar
Dept. of Biostatistics
NIMHANS
Bangalore
India 
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karuna m <m_karuna2002 <at> yahoo.com> writes:
> Can anybody tell me which R package has Lo-Mendell Rubin LR test and
Bootstrap
> LR test to compare the model fit between k class?and k+1 class model 
> for Latent class analysis?
  I don't know, but

library("sos")
findFn("Lo-Mendell")
findFn("{latent class analysis}")

  might help you track down the answers.

Hello there,

I want to perform a likelihood ratio test to check if a single exponential
or a sum of 2 exponentials provides the best fit to my data. I am new to R
programming and I am not sure if there is a direct function for doing this
and whats the best way to go about it?

#data
x <- c(1 ,10,  20,  30,  40,  50,  60,  70,  80,  90, 100)
y <- c(0.033823,  0.014779,  0.004698,  0.001584, -0.002017, -0.003436,
-0.000006, -0.004626, -0.004626, -0.004626, -0.004626)

data <- data.frame(x,y)

Specifically, I would like to test if the model1 or model2 provides the best
fit to the data-
model 1: y = a*exp(-m*x) + c
model 2: y = a*exp(-(m1+m2)*x) + c

Likelihood ratio test = L(data| model1)/ L(data | model2)

Any help would be most appreciated. Thanks in advance.

Diviya

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