Displaying 9 results from an estimated 9 matches similar to: "Problem fitting a non-linear regression model with nls"
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
2004 Jul 28
0
Modelling compound logistic growth curves
Motivated by the discovery of 'loglet analysis'
(http://phe.rockefeller.edu/LogletLab/) that allows one to decompose growth
curves into a series of logistic equations, I attempted to do the same thing
in R.
SIMULATED DATA
Time <- 1:200
pop.size <- SSlogis(Time,10,20,5) + SSlogis(Time,20,100,20) +
rnorm(length(Time))
MY ANALYSIS
results <- nls(size ~ SSlogis(Time, Asym1, xmid1,
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 <-
2002 Jun 07
2
Hope fo help - functions, fits and for cycles
I need a little piece of advice concerning passing data frames
into the functions. As I do a lot of similar fits at a time, I'd like to
write a small function doing the fits for all relevant variables
automatically. However, I usually get error messages of the
following kind:
(I present here a part of a test code).
#####################################################
# Data set:
2006 Mar 28
0
ansari.test (one tailed)
Hello.
I am probably wrong... I am wondering if it could have a mistake
in the code of the ansari.test function. For me, it seems that the function
do not recover the p value at the correct side of the normal law N(0, 1) when it
use
the normal approximation (presence of ties) in a one tailed test.
Exemple :
quanti<-c(197, 205, 228, 234, 237, 195, 233, 226, 244, 227, 259, 185, 198, 253,
207,
2014 May 24
2
R múltiple archivos de salida
Estimado Jorge Velez
Lo que usted dice tiene algo a mi pregunta, pero yo la formule mal. Voy
a preguntar nuevamente con un ejemplo que tiene errores, pero es más
próximo a lo que estoy pensando.
Modelo (con error pero no importa)
modelo <- muerte = edad + sexo + 1!causa
Causa: infarto, infarto, súbita, muerte en tiroteo
El modelo lineal, sobrevida, etc. corre sin inconvenientes (aunque
2007 Feb 15
2
Time of failure, Arrhenius and Weibull distribution
Hi,
I'm currently doing some analyses on time of failure of a product.
I found on the internet some article about the Arrhenius equation, and I can calculate the results with R.
Equation:
k=A*exp(-Ea/R*T)
I can fit a model with lm for this purpose, so far no problem.
But for the confidence interval, how can I use the Weibull distribution?
Or should I use the weibull distribution at all? Or
2014 May 23
2
R múltiple archivos de salida
R múltiple
Estoy pensando en un problema que tendré que solucionar pero aún no
comencé a escribirlo, por lo tanto no hay código en R como para
compartir, sin embargo no tengo idea de cómo realizarlo desde R.
El planteo es el siguiente:
Los datos son en una cantidad necesaria para que el procesamiento
estadístico demore (minutos, horas).
Supongamos dos variables (serían más), la A y la B,
2009 Feb 16
24
como consultar en oracle
holaa todos ante todo un cordial saludo alguien que me pueda ayudar.
se plantea lo siguiente necesito mostrar 2 campos de una tabla los
cuales son mtin_mtin,mtin_descri de una tabla llamada re_tmtinv de esos
dos campos se necesita obtener el codigo y la descripcion,y luego ser
mostrado para despues ser agregados a un formulario.
el problema que tengo es que ya tengo la vista pero esta en blanco