Displaying 7 results from an estimated 7 matches similar to: "Modelling compound logistic growth curves"
2004 Aug 16
0
Multiple logistic curves
Dear list,
Apologies, I have sent this message before but received no replies so I'm
trying again just in case...
Motivated by the discovery of 'loglet analysis'
(http://phe.rockefeller.edu/LogletLab/) that allows decomposition of growth
curves into a series of logistic equations, I attempted to do the same thing
in R.
#SIMULATED DATA
Time <- 1:200
pop.size <-
2010 Jan 13
1
Problem fitting a non-linear regression model with nls
Hi,
I'm trying to make a regression of the form :
formula <- y ~ Asym_inf + Asym_sup * ( (1 / (1 + (n1 * (exp( (tmid1-x)
/ scal1) )^(1/n1) ) ) ) - (1 / (1 + (n2 * (exp( (tmid2-x) / scal2)
)^(1/n2) ) ) ) )
which is a sum of the generalized logistic model proposed by richards.
with data such as these:
x <- c(88,113,128,143,157,172,184,198,210,226,240,249,263,284,302,340)
y <-
2010 Feb 03
1
comparison of parameters for nonlinear regression
Hi,
I have two series of data set (it's measurment of growth but under two
different conditions).
To model these data I use the same function which is :
formula <- y ~ Asym_inf + Asym_sup * ( (1 / (1 + (n1 * (exp( (tmid1-x)
/ scal1) )^(1/n1) ) ) ) - (1 / (1 + (n2 * (exp( (tmid2-x) / scal2)
)^(1/n2) ) ) ) )
After the estimation of the parameters thanks to "nls", I have 2
2009 Jan 24
1
Help with dudi.pca
Dear R-helpers,
I have two data frames, op and em4:
> str(op)
'data.frame': 37 obs. of 5 variables:
$ m : num 0.202 0.336 0.122 0.139 0.14 ...
$ lln : num 0.798 0.643 0.863 0.835 0.823 ...
$ rrn : num 0.789 0.702 0.894 0.895 0.923 ...
$ asym2: num 0.177 0.304 0.108 0.187 0.274 ...
$ asym3: num 0.0755 0.0975 0.0818 0.0651 0.13 ...
> str(rownames(op))
chr
2004 May 18
0
Circular statistics with (direction,size) data
Dear List,
I have circular data comprising direction and size for a number of
observations. I wish to calculate statistics such as the mean direction and
concentration for these data. I note that the CircStats package only deals
with angular data (i.e. "Each observation is treated as a unit vector or a
point on the unit circle". There appears to be no facility for weighting
2007 Sep 17
2
problems with nested loop
Hi, everyone:
R is new to me. I am writing a nested loop to simulate data for t-test. The following code is wrong. The subscript is out of bounds. Could anyone tell me how to revise it? Thanks, Riddle Chin.
result<-matrix(ncol=5, nrow=1000)
colnames(result)<-c('N=20','N=40','N=60','N=80','N=100')
for (i in 1:1000){
for (j in
2009 Apr 16
2
error bars in matplot
Hi,
I was trying to get error bars in my matplot. I looked at an earlier thread, and the sample code that I made is:
#------------------
library(plotrix)
mat1 <- matrix(sample(1:30,10),nrow=5,ncol=2)
ses <- matrix(sample(1:3,10,replace=T),nrow=5,ncol=2)
vect <- seq(20,100,20)
rownames(mat1) <- rownames(ses) <- vect
colnames(mat1) <- colnames(ses) <- letters[1:2]