# Questions tagged [nonlinearity]

This tag is deprecated because it is too broad. Please find a more specific tag.

58 questions
Filter by
Sorted by
Tagged with
0 votes
0 answers
8 views

### Closed-form solution of logistic regression [duplicate]

"For logistic regression, there is no longer a closed-form solution, due to the non-linearity of the logistic sigmoid function". Can someone please explain the above quoted sentence in ...
• 101
0 votes
1 answer
18 views

### If all computed features ( or components ) in Neural Network nodes are positive numbers , does using Relu meaningful?

I am trying to understand the following issue. The reason we use activation functions such as sigmoid,tanh or relu in neural networks is to obtain a nonlinear combination of input features ( x's). My ...
0 votes
0 answers
21 views

### Gretl's nonlinearity test

I would like to know the bibliographic reference for gretl's nonlinearity test. Can someone help me? There are two tests for checking nonlinearity in regression models: Lagrange Multiplier test for ...
1 vote
1 answer
76 views

### Modelling non-linearity for binary independent variables in logistic regression

I have fit a logistic regression where the response variable is binary - whether an interview candidate got the position or not - and the independent variables are a combination of continuous, ...
• 189
9 votes
4 answers
2k views

### A linear pattern occurs on my residual plot: what can I do?

I'm a bit stuck with a problem here and any kind of help would help a lot :) Just to give a clue about my data. I have 6 independant variables (IV) which are: $X_1$ = Population -within a block- $X_2$...
• 91
0 votes
0 answers
11 views

### Variable relationship case: x1 is not correlated to y but x2 which is related to x1 is correlated to y

I would like to know what is the specific term given to this case, or how is this justified in technical words: x1 is not correlated to y but x2 which is correlated to x1 is correlated to y.
• 111
0 votes
0 answers
39 views

### Exploring relation between x and y [duplicate]

While there are numerous methods in exploring relation between x and y upon receiving a new dataset. Yet it seems I can't find any conclusive guide as of the sequence of analysis, e.g. do correlation ...
0 votes
1 answer
60 views

### Dataset with low and non-linearly correlated variables: suggestions on modelling strategies

I have a dataset with low and non-linearly correlated variables and I am interested in assessing the relations between the Independent Variable (IV) and Dependent Variable (DV), however I am not able ...
• 117
0 votes
1 answer
599 views

### Checking linearity in logistic regression

I am conducting logistic regression, and I am a bit confused about the linearity check? I have 18 independent variables, among them, 13 are continuous, and 5 are categorical variables. In this ...
0 votes
1 answer
284 views

### How to interpret p values of a non-linear covariate using pspline in a coxph model

I tested the assumptions for Cox proportional hazards model on my time-to-event data. I found that the assumption of linearity between independent variables and model residuals is violated. After some ...
1 vote
0 answers
89 views

### Does this scatter plot suggest non-linearity?

As part of assumption testing for ordinary least squares (OLS), I am examining the linearity between the variables in my model. I'm using scatterplots between the independent variables (IVs) and ...
• 11
1 vote
0 answers
33 views

### Linear and nonlinear feature extraction methods

I far what i understand, the assumptions for PCA is that data should be linear. What does that imply? let say if i have a data of 1000*100. So all independent variables should be linearly separable ...
5 votes
1 answer
870 views

1 vote
0 answers
51 views

### Left censored dependent variable in SEM

I'm working on a structural equation model in Amos. I have two independent variables, 5 mediators and a left censored dependent variable. The dependent variable is either 0 or a positive amount in ...
• 11
0 votes
1 answer
122 views

### How do auto-encoders or Restricted Boltzmann Machines find high variance components for non-linear PCA?

I have read about auto-encoders and RBMs being used to perform non-linear PCA by forcing the hidden layers to learn a good representation of the input features with reduced dimensions. But how do ...
1 vote
1 answer
156 views

### How to balance/interpret increasing "good fit" statistics, but seeing more departing from linear regression assumptions?

I noticed that I can substantially improve my model's R$^2$ and Residual standard error values by adding some interaction terms. My model's statistics go from: ...
• 3,187
1 vote
0 answers
65 views

### Data transformations in linear model

I'm starting an academic project about transformations in linear models? At the moment I'm listing all the transformations that there are to correct violations on the assumptions of the linear ...
6 votes
1 answer
8k views

### How to detect nonlinear relationship?

I have two continuous variables that may have nonlinear relationship. Scatter plot of two variables showed an ellipse shape. Furthermore, both Pearson correlation coefficient and Spearman's rank ...
• 61
1 vote
0 answers
34 views

### Modelling nonlinear change of outcome in population with unbalanced longitudinal data

I would like to flexibly model the development of some continuous outcome of interest as a nonlinear function of age, using longitudinal data with rather strong imbalance (i.e., most individuals cover ...
• 245
7 votes
0 answers
621 views

### Spinograms vs. conditional densityplots

I have a binary response variable (hail) and multiple continuous predictor variables. My aim is to understand the linear/non-linear relationship of the predictors to the response to be able to justify ...
• 481