Displaying 7 results from an estimated 7 matches for "mod14data2_random".
2023 Aug 20
1
Issues when trying to fit a nonlinear regression model
Dear Bert,
Thank you for your extremely valuable feedback. Now, I just want to
understand why the signs for those starting values, given the following:
> #Fiting intermediate model to get starting values
> intermediatemod <- lm(log(y - .37) ~ x, data=mod14data2_random)
> summary(intermediatemod)
Call:
lm(formula = log(y - 0.37) ~ x, data = mod14data2_random)
Residuals:
Min 1Q Median 3Q Max
-0.7946 -0.0908 0.0379 0.1111 0.5917
Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) -1.81693 0.25806 -7.04 8.8...
2023 Aug 20
1
Issues when trying to fit a nonlinear regression model
...; wrote:
> Dear Bert,
>
> Thank you for your extremely valuable feedback. Now, I just want to
> understand why the signs for those starting values, given the following:
> > #Fiting intermediate model to get starting values
> > intermediatemod <- lm(log(y - .37) ~ x, data=mod14data2_random)
> > summary(intermediatemod)
>
> Call:
> lm(formula = log(y - 0.37) ~ x, data = mod14data2_random)
>
> Residuals:
> Min 1Q Median 3Q Max
> -0.7946 -0.0908 0.0379 0.1111 0.5917
>
> Coefficients:
> Estimate Std. Error t value Pr(&...
2023 Aug 20
2
Issues when trying to fit a nonlinear regression model
...roach you mentioned, then did the following to
fit the nonlinear regression model:
nlregmod2 <- nls(y ~ theta1 - theta2*exp(-theta3*x),
start =
list(theta1 = 0.37,
theta2 = exp(-1.8),
theta3 = -0.05538), data=mod14data2_random)
However, I got this error:
Error in nls(y ~ theta1 - theta2 * exp(-theta3 * x), start = list(theta1 =
0.37, :
step factor 0.000488281 reduced below 'minFactor' of 0.000976562
nlregmod2 <- nlxb(y ~ theta1 - theta2*exp(-theta3*x),
start =
list(thet...
2023 Aug 20
1
Issues when trying to fit a nonlinear regression model
...the following to
> fit the nonlinear regression model:
> nlregmod2 <- nls(y ~ theta1 - theta2*exp(-theta3*x),
> start =
> list(theta1 = 0.37,
> theta2 = exp(-1.8),
> theta3 = -0.05538), data=mod14data2_random)
> However, I got this error:
> Error in nls(y ~ theta1 - theta2 * exp(-theta3 * x), start = list(theta1 =
> 0.37, :
> step factor 0.000488281 reduced below 'minFactor' of 0.000976562
> nlregmod2 <- nlxb(y ~ theta1 - theta2*exp(-theta3*x),
> start =...
2023 Aug 20
1
Issues when trying to fit a nonlinear regression model
...starting values for theta0, theta1, and theta2
in the nonlinear model. This converged without problems.
Cheers,
Bert
On Sun, Aug 20, 2023 at 10:15?AM Paul Bernal <paulbernal07 at gmail.com> wrote:
> Dear friends,
>
> This is the dataset I am currently working with:
> >dput(mod14data2_random)
> structure(list(index = c(14L, 27L, 37L, 33L, 34L, 16L, 7L, 1L,
> 39L, 36L, 40L, 19L, 28L, 38L, 32L), y = c(0.44, 0.4, 0.4, 0.4,
> 0.4, 0.43, 0.46, 0.49, 0.41, 0.41, 0.38, 0.42, 0.41, 0.4, 0.4
> ), x = c(16, 24, 32, 30, 30, 16, 12, 8, 36, 32, 36, 20, 26, 34,
> 28)), row.names = c(N...
2023 Aug 20
3
Issues when trying to fit a nonlinear regression model
Dear friends,
This is the dataset I am currently working with:
>dput(mod14data2_random)
structure(list(index = c(14L, 27L, 37L, 33L, 34L, 16L, 7L, 1L,
39L, 36L, 40L, 19L, 28L, 38L, 32L), y = c(0.44, 0.4, 0.4, 0.4,
0.4, 0.43, 0.46, 0.49, 0.41, 0.41, 0.38, 0.42, 0.41, 0.4, 0.4
), x = c(16, 24, 32, 30, 30, 16, 12, 8, 36, 32, 36, 20, 26, 34,
28)), row.names = c(NA, -15L), class = "d...
2023 Aug 21
2
Interpreting Results from LOF.test() from qpcR package
...gt; LOF.test(nlregmod3)
$pF
[1] 0.97686
$pLR
[1] 0.77025
Can I conclude from the LOF.test() results that my nonlinear regression
model is significant/statistically significant?
Where my nonlinear model was fitted as follows:
nlregmod3 <- nlsr(formula=y ~ theta1 - theta2*exp(-theta3*x), data =
mod14data2_random,
start = list(theta1 = 0.37,
theta2 = -exp(-1.8),
theta3 = 0.05538))
And the data used to fit this model is the following:
dput(mod14data2_random)
structure(list(index = c(14L, 27L, 37L, 33L, 34L, 16L, 7L, 1L,
39L, 36L, 40L, 19L, 28L, 38L, 32L), y = c(0.4...