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Questions tagged [model]

A formalization of relationships between stochastically (randomly) related variables in the form of mathematical equations. DO NOT USE THIS TAG BY ITSELF: always include a more specific one.

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Does this problem satisfy markov properties to be modeled as HMM?

I want to model a chemical reaction network which is defined by a stoichiometric matrix $\nu^{s\times m}$ where $s$ is the number of participating species and $m$ the number of chemical reactions. If ...
5 views

Modelling Technique for Cross Sell, Up Sell and Recommendation [on hold]

I am new to machine learning and exploring statistical techniques to Cross-Sell, Up-Sell and Recommend Life insurance to customers. I have transactional data of customers and their policy details. ...
9 views

Help with model selection [on hold]

In my experimental setup, I have a square symmetric matrix of variables (65) which I'll call A. Aij represents some relationship between the variables. I then performed an experiment in which I have ...
53 views

should I correct for number of models?

I've built about 8 models, each testing slightly different things but within the scope of the same study. ...
17 views

How to analyze data with unequal length of observations and many zeros?

I want to analyze the impact of the rain on smoking probability. I observed people in two cities on the streets and marked the following parameters: city, gender of the person, duration of observing ...
32 views

Events in Panel data set

I would like to estimate the impact that a certain event has on my dependent variable. I hope you can help me. More precisely, I have a panel data set of the yearly number of IPOs for each EU member ...
36 views

How to model count data in which events are not independent

I have data on the number of hospitalizations over one year in patients with chronic obstructive pulmonary disease, and I need to estimate the difference in the number of hospitalization between two ...
218 views

Is it ever possible for a model to attain 100% accuracy on both train and test and has not overifitted?

I'm curious to know whether we have such a case and if they exist how good/bad it is! I'm coming from this question and I'm thinking whether overfitting is an unpreventable concept that occurs ...
27 views

data analysis of categorial dicothomical variables

I have the following dataset I would like to calculate the frequency distribution of the response F or G in each participant, for each condition (MIO,TUO, NEUTRO) for a total of 15 images ...
74 views

Why construct statistics when you can never beat LRT?

This is a soft question, and I hope I can keep it on-topic. According to the Neyman–Pearson lemma, (generalized) likelihood-ratio tests have the highest possible statistical power, yet LRTs are quite ...
20 views

Should Yes/No dependent variable be categorical or continuous in model?

I have a yes/no dependent that I am interested in modeling. Yes means that a bird took a seed, No means that bird did not. Should I code it such that it is read as a categorical variable or a ...
22 views

Should I have a variable as random? [duplicate]

I have put individual ID as a random variable in my model, but some individuals only have 1 record and others have 19 records. Does this mean that individual ID shouldn't be a random variable? ...
7 views

Modeling: Relate the current results to other data

If I want to measure the effect of a feature on apple price. Therefore, I build a linear regression model trained on apple data (feature includes size, color, category etc.) and just look at the ...
7 views

Generalization performance of a model (RStudio)

I'm kind of confused on the definition of generalization. E.g. I've created a model in RStudio, for which I've plotted the training history results: Now I'm wondering, is the generalization of my ...
12 views

“Double censored” model?

How would I properly model the following: A disease has three stages of diagnosis: No symptoms, Mild, Advanced. These are based on behavioral criteria. There are also brain pathology scales that do ...
10 views

Finding the Bias and Residual Components of Mallows Cp

So I have this question but am unsure on how to do it: If a true quadratic regression function is E(Y) = 15+20X+3X^2, and the fitted linear regression function is Y_hat=13+40X, for which E(...
259 views

How can I fit a spline to data that contains values and 1st/2nd derivatives?

I have a dataset that contains, let's say, some measurements for position, speed and acceleration. All come from the same "run". I could construct a linear system and fit a polynomial to all of those ...
104 views

Problematic data for regression model

This is a follow-up question to Which model for my data? (testing the differences in slope for three groups). The solution from there works (big thanks to Heteroskedastic Jim!), but I have a problem ...
19 views

What defines a correct / incorrect model in Bayesian inference when it comes to independence

This might be a very broad question but I'm wondering whether we can say a model of Bayesian inference is "correct" or not about assuming independence. For example, suppose there are $N$ coins each ...
8 views

Is there any algorithms/models to generate embedings of sequential data (other than RNN)?

I know that RNN can be used for such task. For instance facenet used rnn with triplet loss. But maybe there are some less sophisticated alternatives to try first?
34 views

How to write a logit regression in a journal format?

I was inspired by the following question: How to write a logit and probit regression equation? To ask for advice on how to write a logit regression equation in a suitable format for an academic ...
33 views

glmStepAIC model is doing better that other models

I am training a model on an imbalanced dataset (about 5-20% of positive class) and trying out different algorithms in R using caret package. I have 57 predictors and around 2000-3000 observations in ...
59 views

GARCH Model Estimation

I am analysing a GARCH(1,1) model under the assumption of t-Student distribution. In particular, I set the problem in the following way. I have a series ${y_t}, t \in{1,2,...,T}$ and I assume that: ...
14 views

Is this an acceptable approach to SEM / Path Analysis?

I want to test a model in which all possible paths between variables are captured (see fig 1) and then upon reviewing the path coefficients, remove non-significant paths (fig 2). Obviously with fig 1 ...
7 views

By including covariance between mediating variables does my model become recursive?

I am conducting a path analysis and am interested in the mediating effects of two variables (var 3 & 4) which I expect to be correlated with one another. By including covariance between residual ...
17 views

Path Analysis - Can my model include covariance between residuals of endogenous variables?

I am conducting a path analysis and want to include two mediating variables (Variables 3 & 4) which I believe will be correlated with one another. I don't want to specify the direction of this ...
14 views

Efficient Machine Learning Model Evaluation / Performance Estimation

I am currently thinking about ways to efficiently evaluate and estimate the performance of ML models with respect to the runtime and accuracy. I already know standard validation techniques like LOO ...
40 views

post hoc pairwise comparison

I have a model testing whether the modifications to my texts (fixed factor: Modified) affect several measures (for example IA_FIXATION_COUNT). The Texts used in my experiments are 8, and when i want ...
24 views

Modeling background noise with a half normal distribution

I'm working with radiation measurement data and have background noise data with $(\mu, \sigma)$ < 1 and all background measurement values >= 0. If I wanted to approximate/model this noise, would a ...
24 views

Multilevel model method in non-Bayes algo? [duplicate]

I have learned multilevel model in Bayes methods, which I think is really cool. Different levels data could share information which could improve the total model. Is there any similar methods in non-...
8 views

Perturbed Bias Feature

If we have a model that is said bias against gender, we can perturb against gender field like https://cloud.ibm.com/docs/services/ai-openscale?topic=ai-openscale-anlz_metrics_fairness to debias. How ...
90 views

PR AUC < 50% with ROC AUC > 90% - model good or bad?

I understand for highly imbalanced dataset - we need to look for precision-recall vs ROC AUC to better judge the model. My question is what is the range for PR AUC below which the model is bad? My ...
13 views

Using likelihood ratio test to compare 2 nested simple linear models instead of anova

Is it valid to use a likelihood ratio test to compare 2 nested linear models instead of anova? I'm trying to assess whether the quadratic model is a better fit to the data. I know anova seems to be ...
14 views

calculate a variance for a given R-squared [duplicate]

I am trying to replicate a study that has generating simulated data with the following variables and assumptions $x_j\sim U[0,1]$, and $j = (1,2,\dots,N)$ with $$z_j = x_j + \sigma_z \epsilon_j$$ ...
36 views

Higher RMSE but lower MAE and RMLSE. Which model is better? [duplicate]

I am evaluating two machine learning models. The output is count data which has a range of 0 to 30, which most of the output values being small values. Large output values are rare. One model has ...
24 views

logistic regression with conflicting results, so to speak

I was trying to duplicate values by running the same set of data, and my coefficients were different. there is one 0-1 dependent variable, and there are four 0-1 independent variables. I found out ...
30 views

What are assumptions of generalized linear model?

can anyone help me and tell me what I have to check to conduct the generalized linear model in SPSS. (What are assumptions of generalized linear model?). thank you so much for any try to help.
13 views

Path Model with (endogenous) Treatment - which model?

I have collected data on the intention to create a new business of my students. I measured it before the course (t1) and after it (t2). I have data on their absenteeism in class and the time they ...
39 views

How do I interpret this interaction between a continuous variable and a binary variable from a log binomial model?

I'm new to modelling and not sure how to interpret this interaction for a results section. The model output tells me that the interaction between cancer (binary) and age (continuous - one year ...
19 views

Evaluating a model performance

I have a model which generates an expected value of Y with input X. Let say Y is the future stock price and X is difference statistics of the stock (current stock price, P/E, market capital etc...) ...
14 views

How can I analyse the association between a categorical variable (binary outcome) and a continous variable especially in R?

I want to analyze the association between a binary variable and a continuous variable in R. But I am not clear about what steps I should follow. I explored the continuous variable by the histogram ...
19 views

Are Bayesian Networks parametric or non-parametric models?

After searching Wikipedia, I found that there are both parametric Bayesian models and non-parametric Bayesian models. What about Bayesian Networks? When building up a Bayesian Network model, I don't ...
28 views

Which methods would you use in case of binary data? [closed]

The dataset is a full ranked binary dataset. Therefore, Y = 1 or 0and X's = 1 or 0. Y represents whether a car has an engine ...
27 views

What is the full form of BRP in Machine Learning?

In this paper, the author has mentioned about a model named BRP related to Machine Learning whose full form has not been provided. I googled the term BRP but couldn't land to a reliable answer. Is it ...
26 views

What if a feature fully available for training is not fully available in test instances?

In training a model, I know that there exists a feature that is fully available during training, but will be available only in 15% of test instances when the model is deployed. How to handle this ...
46 views

addressing the effect of the independent variable on the dependent variable for 2 different types of individuals

I am estimating the effect of a continous treatment X (that goes from 0 to 1) on a dependent variable y (data is taken through an experiment). I have around 250 Individuals in my dataset that can be ...
48 views

Model simplification

I am currently looking at a linear mixed model of with the formula x ~ y * z I'm struggling with simplifying the model. When I run an ANOVA of my model it said ...
46 views

Weibull Model in Stata vs R

I am currently trying to replicate a study on war duration, which used Stata's streg function to estimate a parametric Weibull model. The stata code reads: ...