Questions tagged [nonlinear]
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352
questions
4
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2
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If R2 is not appropriate for non-linear ML algorithms such as Random Forests, can a Pearson or Spearman correlation be used as performance metric?
$R^2$ is not appropriate for non-linear models, such as Random Forest (RFs) models.
https://arxiv.org/pdf/1611.03063
Is R-squared truly an invalid metric for non-linear models?
https://...
- 1,037
3
votes
1
answer
38
views
Nonlinear indirect effect in lavaan & semTools
I would like to use semTools to examine several indirect effects. However, some predictors have nonlinear relationships (i.e., quadratic) with the mediators, but I found very little information online ...
- 171
0
votes
0
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31
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Sufficient number of data to determine whether a model fits the data well
I was wondering if, chosen a proper mathematical model, there is a minimum number of data that allows us to state if the model fits well the data or it doesn't.
I'll explain better my question. Let's ...
- 1
0
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0
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10
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How to interpret Diffusion Maps for the iris dataset?
This might be a poor exercise but I'm trying to understand the methods of paper and if it makes sense to adapt my linear-based workflow with PCA to non-linear manifold methods; thought trying out ...
- 1,472
0
votes
0
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27
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OLS and Linear and Nonlinear Models
I understand what linear (w.r.t. coefficients) models are. For example, the power model $Y=k X^p$ is nonlinear..$Y= \beta ^X$ is also nonlinear, etc.
Ordinary-least-squares (OLS) is one of the many ...
- 91
0
votes
0
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21
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Identifications for the linear and non-linear models
Consider a linear model and a non-linear model:
$$Y=X'\beta+u$$
$$Y=m\left(X;\beta\right)+u$$
Then, in my understanding, the identification conditions for $\beta$ in the linear model are
Condition 1: ...
- 401
3
votes
1
answer
32
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Nonlinearity of model using Sobol indices
I'm analyzing a computationally demanding numeric model where I want to show that nonlinearities play a certain role for my problem. I want to do this using Sobol sensitivity indices of first oder by ...
- 41
5
votes
1
answer
115
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How to estimate this specific logistic regression model which is not linear in its parameters?
A. Suppose I want to fit the regression
$Y = f(\lambda X_1 + (1-\lambda) X_2)$
where $f(x) = ax^2 + bx + c$, and $\lambda$, a, b, c are to be estimated using the data.
This is nonlinear, but it's ...
- 939
1
vote
0
answers
66
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crossed random effects in nonlinear mixed-effects model
I am a beginner in mixed effects modeling and am trying to find some useful code to solve my current problem. Specifically, I'm having some problems with model fitting. I'm looking for a ...
1
vote
1
answer
82
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Interpertation of a conditional quadratic latent growth curve model (i.e., with predictors)
I have a conditional quadratic latent growth curve model and am wondering how to interpret the results.
My predictor of interest is significantly associated with the slope factor (B = -0.45, p = .001) ...
- 309
0
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348
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How to calculate covariance matrix in nonlinear least squares
I am fitting a nonlinear model to observations by using least squares to estimated the model parameters.
Theoretically, the covariance matrix of the parameters can be estimated by inverting the ...
- 31
1
vote
1
answer
80
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Specifying continuous autoregressive covariance structure in multilevel daily diary model
I have a daily diary dataset with daily ratings of mood (e.g., daily rating of happiness) between two treatment conditions. The complete number of days of ratings vary widely across participants and ...
- 31
1
vote
1
answer
68
views
Can All Regression Supervised Machine Learning Models Be Viewed as Linear Models Over Transformed Features?
I've been studying various supervised machine learning algorithms for regression tasks, and I've come across an interesting perspective suggesting all machine learning models could be represented as ...
1
vote
0
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34
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Regression model : does non-linearity imply interaction effect?
I would like to know more on the relation between non linearity and interaction effect. For example, if we have a linear model of the form
$$
y = \beta_0 + \beta_1x_1 + \beta_2x_2 + \epsilon
$$
we ...
- 111
0
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0
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159
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Multiplicative linear model
I am considering the model:
$$
y_t = \beta_0\left(\Pi_{i=0}^{K}x_{i,t}^{\beta_i}\right)\left(\Pi_{j = K+1}^{L}e^{\beta_{j}x_{j,t}}\right)
$$
where we want to have multiplicative effect between ...
- 111