A statistical model is a formalization of relationships between variables in the form of mathematical equations. The model is statistical as the variables are not deterministically but stochastically related.

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What are possible theories/models to describe social influence based on frequency?

I am working on social influence based on frequency, meaning if a person repeatedly appears at a location many times then he/she is more influential at that location. In other words, he/she can ...
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1answer
18 views

Determining if time has influence on correlation between x and y

Is there a sort of statistics model I could use to determine if time has an influence on the correlation between two sets of data? For example say I have a column $X$ and a column $Y$, both just ...
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Am I using the correct model, if so what do I need to fix?

I am seeking to model the number of high tunnels on farms with 13 other factors. Factors include: lattitude, percent of the population with food access, percent of vegetable acres per county, ...
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1answer
18 views

Estimating costs with extreme values

I am trying to estimate health care costs and I was wondering what the standard practice is for extreme values? By extreme values I mean I have a large portion of my costs being zero and a small ...
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0answers
27 views

How to correctly choose model based on BIC?

I have a question about Bayesian Information Criteria. (GARCH models) I have looked for so many hours but still very confused about this BIC especially a negative one. As far as I am concerned it is ...
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1answer
24 views

Interaction model significant in multiple linear regression

This question is not about interaction effect, but about interaction model in Hierarchical Linear Regression. I have 1 DV and 5 IVs. I want to see which of the IVs is significant predictor of DV. ...
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1answer
29 views

Clustering Two Variables With Disease Information

I was proposed a problem and I am not quite sure how to go about it. The problem is I want to find a relationship between two variables. For the simplified case there are only two variables, lets say ...
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13 views

Variables occurring after target occurence, can they be used in regression model?

My study is to judge the appropriateness of target=1, not for predictive purpose. Can the variables occurring after target occurrence be used in regression or decision tree model? For example, a ...
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1answer
22 views

Which is better ROC curve or Confusion matrix?

anyone know about the predictive model evaluation? I'm confused about the ROC curve and confusion matrix. The area under the curve for ROC is represent about the accuracy of the classifier. But what ...
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37 views

How to validate goodness of fit and forecasting quality of a model?

I am working on big data sets, which represent electricity consumption on power substation throughout the year. I have data every 10 minutes and multiple (and long) seasonalities. I have a daily, ...
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6 views

HLM-related inquiry - comparing the magnitude of coefficients

I've conducted two separate HLM analyses, each with two IVs predicting to the same DV in the same sample. The problem that I've encountered is that I would like to compare the magnitude of the ...
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16 views

Design of Experiments

Help me point out the differences between mixed-effects model, subsampling model and split-plot model. Thank you very much in advance!
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1answer
28 views

Binomial model of true/false test taker

I have a very large number of true/false questions. I want to take a sample of these questions and use them to test a subject. I would like to infer the proportion of questions out of the larger set ...
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1answer
50 views

Non-significant factors after stepwise regression [duplicate]

I have run a stepwise regression on R. However, the summary of the final model includes some factors that are not significant. Why have these factors not been removed? Should I remove these from my ...
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1answer
36 views

Why do my ANOVA tables keep returning $\chi^{2}$ values of 1?

I'm using ANOVA to test for differences between different values of the same factor for a mixed effects model which I produced. My model is: ...
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1answer
29 views

Difference between significance and contribution

"What is the difference between "significance" and "contribution" of individual variable to a outcome variable? How to address this while creating a prediction model basically.I understand ...
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0answers
12 views

Model creation under PLS

I'm developing prediction model based on PLS (partial least squares) analysis. I'm looking into variation captured by X(R square X), R square Y, number of components and accuracy after using cross ...
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0answers
25 views

mixed model vs. markov chain

I have a longitudinal data with multiple time points (measured twice every year). There was seasonal difference on the outcome variable of interest (BMIz) if using mixed model (where time points were ...
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2answers
28 views

Evaluate mixture model

I have a question concerning the evaluation of mixture models. Is there a gold standard to compute the goodness of a fit for a mixture model? What I am concerned about is how one would evaluate if ...
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0answers
12 views

What is a “concordance score” for regression coefficients?

I came across this "concordance score" in a set of slides called Penalized regression methods for ranking variables by effect size, with applications to genetic mapping studies, by Ji Zhu: $$ ...
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0answers
22 views

Evaluating the temporal corelation model for which the differencing is performed for trend removing

According to the literature, for temporal correlation modeling the trend should be removed from the time-series data. We choose differencing for removing the trend. I would like to know: When we ...
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0answers
49 views

Is it possible to build a curve with a given skewness and kurtosis?

I have data in the following form: Day Kurtosis Skewness Total Inflows 163 .3 .5 435670 I'm attempting to do some modeling of an inflow ...
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1answer
29 views

Structural Equation Models - building with a large sample, and testing with a small one?

I'm planning a study using Structural Equation Modelling to test different accounts of language learning. I would like to study a group of children with language difficulties. However, they are very ...
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1answer
64 views

Time series estimation on specific lags in ARMA model

How can I fit this ARMA model having specific lags using R?
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0answers
43 views

Tukey for GLM can't find data in model

I fit a GLM to a dataset. Now I want to see where the difference between my groups is, so I tried to run a Tukey HSD as a post-hoc test. Because of it is a GLM, I can't use ...
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1answer
60 views

Data Mining, generating a model from a database

I have a database with different variables which contains information such as age, date of vaccination, number of doses as well as the number of antibodies (which is my target variable). If the number ...
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1answer
90 views

Logistic Regression - Model Does not Fit

My name is Abhi and I am fairly new to statistics. I found some sample exercises online & I am trying to solve them to get a better understanding of model development. Problem Statement Assume ...
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14 views

RMSE for Model Validation and Calibration

Based on UK's Framework for Marine and Esuarine Model Specification,the % RMSE for current speed is calculated by dividing RMS by maximum peak current. $$\text{RMSE(%)} = ...
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0answers
34 views

Quality of PLS Regression at different interaction levels

I am fairly new to multivariate statistics and have run into the following situation: I have a data set of 12 response sets based on a Likert scale (1-5), data which is commonly (in social research) ...
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2answers
33 views

How many parameters in this specific linear model with interaction?

I have a question where I am not sure about the answer: A linear model has the following characteristics: *A dependent variable ($y$) *One continuous variable ($x_l$), including a ...
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0answers
65 views

ARIMA - SARIMAX modelling with R

I am really new to R and to time series. My field of studies is in the field of Networks and Telecommunication, but my summer internship is about trying to find a statistical model for some sets of ...
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1answer
22 views

Reparametrisation of a model when an interaction is significant to facilitate the interpretation

It is admitted that it is complex to interpret main effects when they are involved in an interaction. Lets take a regular linear model, with two categorical 2 level variables A and B who are ...
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43 views

Taking into account Bayesian model uncertainty

I recently received a review of a paper from a Bayesian Statistics Journal. The Associate Editor wrote this mini-review (quoted below in full). The paper is talking about Bayesian modeling of DNA ...
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0answers
16 views

How to incorporate a noise model into a probabilistic model?

Let's say have a probabilistic model $m$ which I fit to data using maximum likelihood. Now, I would like to add a noise model $n$ which I can also fit independently using maximum likelihood. So I am ...
3
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3answers
133 views

Percentage outcomes in linear regressions

I have a study where many outcomes are represented like percentages and I'm using multiple linear regressions to asses the effect of some categorical variables on thes outcomes. I was wondering, ...
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1answer
30 views

How to make use of known constants when modeling from data?

As a (perhaps contrived) example, let's say we want to discover from some empirical data Coulomb's law for an electric field: $$F = \frac{1}{4 \pi \epsilon_0} \cdot \frac{|q|}{r^2}$$ In this case we ...
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0answers
123 views

Are world cup predictions testable?

As of today, dozens of soccer world cup predictions exist, some more complex, some more elegant, and most of them predict every nation's "chance" of winning a particular match/ the cup. As I am ...
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0answers
29 views

Good (2d) visualization of a mixture model clustering

I have a specific problem which I'm surprised I don't find answers on-line and I hope somebody here has a good suggestion for me. I'm working with a large data set which I'm clustering into specific ...
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0answers
20 views

Variable Construct (Dimension) Insertion (Representation) in SmartPLS

I have a question please. I am working on SmartPLS. The question is regarding variable construct representation. Any variable could have construct including dimensions. For example, the ...
4
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2answers
66 views

Variance as a function of parameters

I am currently building a statistical model. According to data, the variance is non-constant, and it is likely based on a factor. Is there any statistical model with variance as a function of other ...
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1answer
47 views

Machine Learning on Percent/Continous Dependent Variable

I have a large dataset of 30,000 cases with 150 variables. I am looking for a few possible machine learning solutions/methods that I could try and use for cross validation. My dependent variable ...
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0answers
13 views

statistical inference [duplicate]

I guess this issue must be somehow cliched, yet I wasn't able to find the answer that would satisfy me. The key role of statistics and econometrics is to make inference about population using some ...
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6answers
588 views

When forcing intercept of 0 in linear regression is acceptable/advisable

I have a regression model to estimate the completion time of a process, based on various factors. I have 200 trials of these processes, where the 9 factors being measured vary widely. When I perform a ...
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0answers
19 views

Hierarchical Linear Modeling - Summation in Level 1

I'm currently trying to write a Level 1 model for the following research question. RQ: Does the school-level relationship between race and the proportion of reading proficient students (outcome) vary ...
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1answer
14 views

On which data should the lift be calculated i.e. Training set or Test set and why?

On which data should the lift be calculated i.e. Training set or Test set and why? What does the lift value 115% mean
2
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1answer
40 views

Is it possible to analyze a problem using graph if number of features is greater than 2?

By graphing, you can see if the data is linear or not, basically you can analyze the structure of your data easily and you can then decide which model to use. If you have, say, one feature, you can ...
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0answers
26 views

linear mixed models differences between groups

I should test if the differences between 5 groups are statistically significant. I should use linear mixed models with restricted maximum likelihood. Group and time should be my fixed factors and the ...
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6answers
231 views

Textbooks pertaining to creating models?

I'm not sure if a question like this has been asked yet on this website. I recently graduated as an undergraduate statistics major with a bit of a dense math background (I know some probability ...
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1answer
61 views

Determine penalty parameter based on AIC values in lasso regression for linear mixed model

I have a dataset with 14 variables, of which one random effect (Patient) I fitted following code: "fit1_B2=lmmlasso(y=y,x=x.matrix,z=z,grp=grp,lambda=0.1,pdMat="pdIdent") summary(fit1_B2) ...
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1answer
38 views

Testing the influence of monthly fluctuations

Let's say we have a dataset that looks like this: ...