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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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10 views

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 ...
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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. ...
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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 ...
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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. ...
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1answer
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 ...
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0answers
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 ...
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1answer
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 ...
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1answer
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 ...
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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 ...
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1answer
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 ...
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1answer
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 ...
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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? ...
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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 ...
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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 ...
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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 ...
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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(...
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3answers
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 ...
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1answer
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 ...
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1answer
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 ...
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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?
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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 ...
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1answer
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 ...
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2answers
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: ...
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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 ...
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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 ...
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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 ...
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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 ...
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1answer
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 ...
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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 ...
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0answers
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-...
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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 ...
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2answers
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 ...
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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 ...
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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 $$z_j = x_j + \sigma_z \epsilon_j$$ ...
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1answer
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 ...
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1answer
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 ...
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0answers
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.
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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 ...
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1answer
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 ...
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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...) ...
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2answers
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 ...
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0answers
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 ...
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0answers
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 ...
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1answer
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 ...
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0answers
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 ...
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2answers
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 ...
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2answers
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 ...
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0answers
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: ...
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0answers
36 views

Cross validation or percentage split

I got a data-set with 50 different classes. Around 40000 instances and 48 features(attributes), features are statistical values. I am using weka tool to train and test a model that can perform ...
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0answers
13 views

Regression model for categorical DV with more than 2 response options

I am soon going to start running a simple behavioral experiment where each response will be coded as belonging to one of 3 categories (or otherwise, as NA). I ran a similar experiment before, where ...