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2
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0
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79
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Why does survival::survreg produce an extreme estimation?
In the context of a simulation study, I simulate many survival datasets including the following variables:
trt: whether the patient received treatment or placebo (0/1)
Evt: whether the patient died ...
2
votes
2
answers
128
views
Weibull Predictions using R and current component hours
I have failure data for tire removals that I have fitted to a weibull distribution, which has parameters beta = 1.09 and eta = 2750. Using the weibull parameters I would like to apply this to another ...
0
votes
1
answer
74
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Problems with fitting the "fitdist" distribution parameters
Good afternoon, dear colleagues. In the process of working on the project we have problems with fitting the parameters of the distribution law using the maximum likelihood method. Please help me to ...
0
votes
1
answer
103
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Why are parameters returned by scipy's weibull_min inaccurate?
I'm trying to (1) simulate data with a Weibull distribution using known parameters, and then (2) trying to fit that simulated data with a Weibull function and get parameters back. The idea is that I ...
0
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0
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30
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How do I address error "Error in model[[k]][[2]][[2]] : object of type 'symbol' is not subsettable" in context of Weibull mixed model in merlin in R?
I am trying to model tree diameter distributions from a series of sites using a mixed-effects model. This model assumes that data follow an underlying Weibull distribution. This is all being done ...
1
vote
1
answer
74
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Should i optimize all three parameters of a weibull distribution function at the same time in a python script?
I want to optimize coefficents for the scale, shape and location function for a weibull PDF.
this is the code:
import numpy as np
from scipy.optimize import minimize
from scipy.stats import ...
0
votes
1
answer
239
views
Weibull Three Parameters Estimation using Maximum Likelihood and optimization methods
I'm having a problem estimating the Weibull three parameters using ML and optimization methods. My results in some of the methods do not look right. However, when a plot the curve looks fine with the ...
0
votes
1
answer
47
views
Why do i have this gap in my plots during a weibull fitting with a 3 parameter pdf function?
I want to fit data to a 3 parameter weibull distribution, but on my plot i have always a gap between the original data and the fits. What do i am wrong? And why do i get such a worst fit when i use ...
0
votes
1
answer
1k
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Is there a Python function for generating Weibull probability plots like wblplot() in Matlab?
I would like to reproduce the same graph as shown on Matlab's wblplot() documentation:
Matlab wblplot() documentation
I am wondering if there is a way to generate this on Python, either with an ...
2
votes
1
answer
128
views
Calculate CDF of Weibull distribution in R
I want to calculate the probability that a Weibull random variable X is greater than 1000, where X ~ Weibull(lambda, g).
Using the CDF I calculate it as:
g = log(log(.7)/log(.5))/log(40/81)
lambda = -...
0
votes
1
answer
199
views
How to find the x-intercept of Weibull distribution
I am trying to write a code to plot Weibull probability. I want to find the scale parameter which is the x-intercept where the fitted line intersects with probability = 63.2%. Also the slope is very ...
1
vote
0
answers
52
views
Parametric survival in R
I have been trying to do a survival forecast at 5 years using a parametric model (Weibull), but I am having problems calculating a 95% CI.
I tried (using the dataset lung that comes with survival):
...
0
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0
answers
395
views
How to create Histogram density plot in SAS but with already predicted and observed values?
I'm working on a paper that characterize the tree diameter distribution using Weibull. I have tested some parameter prediction and parameter recovery methods and I obtained the results. My results ...
1
vote
1
answer
234
views
Weibull probability plot with R and plotly
I'm attempting to build a Weibull probability plot with R and plotly, but have been unable to set the y-axis values correctly (i.e. the plotted markers don't correspond with the positions given in the ...
0
votes
1
answer
118
views
Weibull Distribution Returns NULL value in R
I'm trying to calculate the shape and scale based on mean and standard deviation of a weibull distribution. If mean = 0 and sd = 1, the shape and scale both return NA. But for other values(such as ...